BACKGROUND OF THE INVENTION CROSS REFERENCE TO RELATED APPLICATION This application claims the benefit of U.S. Provisional Application No. 61/639403, filed April 27,2012, which is incorporated by reference in its entirety. The field of the invention relates generally to gas turbines, and more particularly to methods and a system for a seal assembly for an inter-shaft seal in a gas turbine engine. Labyrinth seals are widely used on rotatable shafts to regulate secondary air flows and provide a radial clearance between low speed shafts and high speed shafts in gas turbine engines. Generally, in more detail, the seals include a series of parallel teeth that facilitate regulating a flow past the teeth and capturing any excess oil. The tips of the teeth provide the clearance between the two shafts. Newer generation engines include shafts made of strong, but brittle materials that may not be as tolerant of the rubbing that typical seal teeth endure during engine operation. The rubbing can cause localized micro-cracking in the shaft. Seals made of a single unit that are integral to the shaft may not be allowable in some situations due to material or stress concerns. Additionally, sections of greater shaft diameter located both forward and aft of the seal can prevent implementation of the seal on an unbroken ring of material. Accordingly, a seal that is separable and not subject to the torque load of the shaft, which results in greater flexibility in design at a lower cost for repair and maintenance is desirable. BRIEF DESCRIPTION OF THE INVENTION In one aspect, a seal assembly for sealing a rotatable shaft in a gas turbine engine, wherein the shaft includes sections of greater shaft diameter located both forward and aft of the seal shaft coupling point is provided. The seal assembly includes a first semi-annular segment with a first end, a second end, and a plurality of seal teeth, where the first and second ends each include an overlap joint. The seal assembly also includes a second semi-annular segment with a first end, a second end, and a plurality of seal teeth, where the first and second ends each include an overlap joint. The first end of the second segment is coupled to the first end of the first segment, and the second end of the second segment is coupled to the second end of the first segment. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of an exemplary gas turbine engine assembly for use in propelling an aircraft. FIG. 2 is an enlarged cross-sectional view of the exemplary seal shown in FIG. 1 in relation to the first and second shafts. FIG. 3 is a perspective view of an exemplary seal in accordance with the present invention. FIG. 4 is a cross-sectional view of the seal on the first shaft taken at line 4-4 in FIG. 3. FIG. 5 is a perspective view of an alignment pin connecting the two segments of the seal shown in FIGS. 3 and 4. FIG. 6 is a perspective view of an alternate embodiment of the seal in accordance with the present invention. FIG. 7 is a cross-sectional view of the seal on the first shaft taken at line 7-7 in FIG. 6. FIG. 8 is a perspective view of an alternate embodiment of the seal in accordance with the present invention. FIG. 9 Is a cross-sectional view of the seal on the first shaft talcen at line 9-9 in FIG. 8. DETAILED DESCRIPTION OF THE INVENTION The following detailed description illustrates an inter-shaft seal and a method of assembling the same by way of example and not by way of limitation. The description enables one of ordinary skill in the art to make and use the disclosure, and the description describes several embodiments of the disclosure, including what is presently believed to be the best mode of carrying out the disclosure. The disclosure is described herein as being applied to a preferred embodiment, namely, an inter-shaft seal and a method of assembling the same. However, it is contemplated that this disclosure has general application to shaft seals in a broad range of systems and in a variety of industrial and/or consumer applications. FIG. 1 is a cross-sectional view of an exemplary gas turbine engine (GTE) 10. GTE 10 includes a fan assembly 12, a core gas turbine engine section 14 coupled downstream from fan assembly 12, and a low-pressure turbine 16 coupled downstream from the core gas turbine engine section 14. In the exemplary embodiment, core gas turbine engine section 14 includes a multi-stage booster compressor 18, a high-pressure compressor 20, a combustor 22, and a highpressure turbine 24. GTE 10 also includes an inlet 26 and an exhaust 28. In the exemplary embodiment, low-pressure turbine 16 and booster compressor 20 are coupled together via a first drive shaft 30, and compressor 18 and high-pressure turbine 24 are coupled together via a second drive shaft 32. In operation, air is drawn into engine inlet 26, and compressed through booster compressor 18 and high pressure compressor 20. The compressed air is channeled to combustor 22 where it is mixed with fuel and ignited to produce air flow through high pressure turbine 24 and low pressure turbine 16, and exits through exhaust 28. FIG. 2 is an enlarged cross-sectional view of the gas turbine engine shown in FIG. 1. GTE 10 includes a seal 34 coupled to first shaft 30. Seal 34 is separable from shaft 30 and includes at least two segments such that it may be installed or removed on a complete shaft without needing clearance on either end of the shaft. Moreover, being made of at least two segments facilitates installation of seal 34 on a shaft even when the shaft has a greater diameter on both sides of seal 34 installation point, which provides much greater flexibility in where seal 34 is located on a shaft. Seal 34 may include, as desired, labyrinth tooth material of the same material, or different material, as/than the shaft 30, respectively. Seal 34 may be coupled to shaft 30 in multiple ways, which are described below. FIG. 3 is a perspective view of an exemplary seal 34 in accordance with the present invention. Seal 34 includes a first half circle-shaped segment 300 and a second half circle-shaped segment 302. First segment 300 includes a first end having a connector 304 and a second end having a connector 306. Second segment 302 includes a first end having a connector 308 and a second end having a connector 310. First segment 300 and second segment 302 assemble by an overlap joint, by joining connectors 304 and 308, and connectors 306 and 310. The overlap joint allows seal 34 to carry a hoop load. Segments 300 and 302 each include a plurality of seal teeth 312. FIG. 4 is a cross-sectional view of seal 34 (shown in FIG. 3) coupled to a shaft tal