packaging: setup: skipping database checks if DB is empty

The current asynctasks and dbvalidations checks are run
during all upgrade flows.

The new implementation runs these checks on upgrade flows
only if DB is not empty.

Change-Id: Id95beac6054843b67dc2ea3311e664d9d194e9ab
Signed-off-by: Alex Lourie <alourie@redhat.com>