Don't include git commit from a parent directory in the --version output
Don't include git commit from a parent directory in the --version output

This can happen when building RPMs out of tarballs (which don't contain
the .git repository).

To test:
> make -n /bin/skopeo; mv .git ../.git ; make -n bin/skopeo

Fixes #1707 .

Signed-off-by: Miloslav Trmač <9c008e38982a5397deb855345fb164f0558459ae@redhat.com>

mtrmac/skopeo,mtrmac/skopeo,mtrmac/skopeo