patch ModelGitMergeEditorInput for EGit 5.3.0 compatibility

This applies the same patch as was done for bug 543495 to EMF
Compare's ModelGitMergeEditorInput.

Bug: 544761
Bug: 543495
Change-Id: I7f916e88a0200d8b552dd353c9278f0e619c800c
1 file changed