security/libcryptui: accept current gnupg 2.3 in configure

Massage our crummy REINPLACE to also accept the current version
of gnupg that is in ports, so this can build agani. While here,
fix the pkg-descr which was still a copy of seahorse (from which
this package was split several years ago).

Upstream has marked this as "likely to be deprecated", and there
has been no release in 4 years. There *has* been an upstream
commit doing what our REINPLACE does, up to gnupg 2.2.