don't install the gpg-zip.1 manpage, avoids CONFLICT with gnupg1,
noticed by OBATA Akio per mail to pkgsrc-users.
This makes most sense to me since gnupg2 doesn't install a gpg-zip
intentionally. Since possible clients of gpg-zip should have a
dependency on gnupg1, we can't take over easily. Once we are sure
that gnupg2 can fully replace gnupg1, we might consider to install
eg symlinks gpg->gpg2 etc and make gnupg1 obsolete, but this needs
careful testing.

(drochner)