pacman-key: import everything then revoke on --populate
The optimization of only importing keys that were not to be later
revoked was a not smart enough. For example, if a key was
in both a repos keyring and its revoke list, alternate runs of
pacman-key --populate would add then remove the key from the pacman
keyring. This problem is made worse when considering the possibility
of multiple keyrings being imported.
Instead, import all keys followed by the revoking of all keys. This
may result in a key being added then revoked, but that is not much of
an issue given that is a very fast operation.
Signed-off-by: Allan McRae <allan@archlinux.org>