Auto merge of #209 - micbou:windows-update-omnisharp-server, r=Valloric

[Windows support] Update OmniSharpServer submodule

OmniSharp Server was modifying the drive letter case of paths causing test failures on ycmd side. This is fixed upstream (see PR OmniSharp/omnisharp-server#207) so we need to update the submodule.

Fix 6 tests (1 error and 5 failures) on Windows (listed in the commit message).