Fix error handling on invalid regex
Fix error handling on invalid regex

Say that the regex is the cause, include it in the error message,
and don't continue as if the compilation succeeded.

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

mtrmac/skopeo,mtrmac/skopeo,mtrmac/skopeo