Set upgrade.target back to archive (from unarchive)
When upgrade_action is set to 'archive' we get this sequence of events:
fetch/configure/build/destroot/archive new version
uninstall old version
install new version
With upgrade action set to 'unarchive' (as it is currently) we get this sequence:
uninstall old versino
fetch/configure/build/destroot/archive/install new version
Changing it to 'unarchive' allows one to copy archives over and have upgrade 'just work', so changing it back will also lead to some undesired behavior (but less undesired I think, and probably easier to fix the archive target to check for an existing archive and not re-create it without force than to modify the sequence of events for the unarchive target).
