gpg-interface: find the last gpg signature line
A signed tag has a detached signature like this:
object ...
[...more header...]
This is the tag body.
-----BEGIN PGP SIGNATURE-----
[opaque gpg data]
-----END PGP SIGNATURE-----
Our parser finds the _first_ line that appears to start a
PGP signature block, meaning we may be confused by a
signature (or a signature-like line) in the actual body.
Let's keep parsing and always find the final block, which
should be the detached signature over all of the preceding
content.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Ben Toews <mastahyeti@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>