test-subrepo: fix globs for Windows
It looks like these changes originated with
2538b87660be. I'm not sure that it
was intentional, but is seems harmless enough for an error message.
tests: diff -r on Solaris emits "Common subdirectories:"
When using the -r option to Solaris diff, any directores that compare
identically are mentioned in the output. We don't really care about these
directories for the purposes of this test, so ignore them.