Allow checkout subdirectory to be expanded (as in specified via build parameter).
Fix bug where subdirectory field wasn't filled in when editing project configuration (and then when saving the configuration the field would be lost).
Do not run file system checks designed for POSIX OS's on non POSIX OS's.
Merge remote-tracking branch 'refs/remotes/origin/hgexetest_posix_path_conditional'

Conflicts:
	src/test/java/hudson/plugins/mercurial/HgExeTest.java