* A package failed to be upgraded properly if current pkg contained
INSTALL/REMOVE scripts, while the new one didn't have any of them.
Fixed this by always removing current scripts if they exist.
* Essential pkgs are never removed (they are replaced) so the pre remove
action target was never called, now it all works properly.
Bumped XBPS_RELVER because I consider these bugs so important.
--HG--
extra : convert_revision : xtraeme%40gmail.com-20100118184932-pdsb0djvf0swylm3
e11a1fe651