security/gnupg: rebuild man pages
gnupg ships its man pages as texinfo files, precompiled into info files.
This patch rebuilds those info files. There are two reasons:
- Rebuilding them automatically corrects several Linuxisms in paths (e.g. /etc => /usr/local/etc).
- Rebuilding them is a neccessary precondition for making any local changes that will affect the content of the man pages, which I intend to do in a future patch.