Directory: Make sure the /* suffix uses correct slashes

When applying the /* wildcard suffix to a directory, make sure the
direction of the slash getting appended is consistent with the other
slashes in the path, i.e. /foo/bar and /foo/bar/ become /foo/bar/* and
similarly \foo\bar and \foo\bar\ become \foo\bar\*.

Change-Id: I44fcf7e97be65923a37aaed615ba5f4012756893