core: Ignore temporary tables exists in engine database

Ignore temporary tables exists in engine database upon upgrade.

Change-Id: I3664a60e1e97e52875882864995e41f3776f7fcd
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1034929
Signed-off-by: Eli Mesika <emesika@redhat.com>