Andrew Gregory authored Feb 21, 2016 and Allan McRae committed Feb 23, 2016

Relying on localdb to determine which trigger operations should match is
completely broken for PostTransaction hooks because the localdb has
already been updated.  Store a copy of the old version of any packages
being updated to use instead.

Fixes FS#47996

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
Signed-off-by: Allan McRae <allan@archlinux.org>