release-2 area tweaked slightly

[Christopher Faylor]

Corinna was noticing some oddities in the release-2 area that I've just
tried to fix.  The ownership of files should now default to
cyguser:cygwin from now on and that should theoretically eliminate
problems when deleting files or changing protections.

The big problem with my optimistic use of a unionfs is apparently that
the sourceware.org kernel is not new enough to encompass some bug fixes
which would make this work better.  I think it is still worthwhile to
continue using a unionfs here but if you notice problems please send
them here.

cgf