packaging: setup: Ask whether to backup the database

Also rollback db at cleanup stage (env overridable) to allow starting the
engine service early if needed.

Change-Id: I8e113bddaeeb71b00f5a524db0be3a24fa6f9907
Bug-Url: https://bugzilla.redhat.com/1059286
Signed-off-by: Yedidyah Bar David <didi@redhat.com>