Pacman package hardcodes systemd socket ignoring GPGDir option

Description:

Since commit 1aec1de5, the pacman PKGBUILD bundles some systemd sockets activated by default that are harcoded to /etc/pacman.d/gnupg dir.

This goes against the ability of pacman to have the gnupg directory elsewhere.

Steps to reproduce:

1. pacman-key --gpgdir /var/lib/pacman/gnupg --init
2. pacman-key --gpgdir /var/lib/pacman/gnupg --populate
3. Add the option GPGDir = /var/lib/pacman/gnupg/ in /etc/pacman.conf
4. Make /etc read-only system-wide.
5. Even if /var/lib/pacman/gnupg/ is writable, the services installed by the package will be failing on reboot.