core: Upgrade - Error Can't start the ovirt-engine-dwhd service

Fix column name to _update_date instead of update_date
Add column to all relevant tables in fixtures.xml

Change-Id: If99b9dca0f1b83f1a815d4ebb112828a135e495a
Signed-off-by: Eli Mesika <emesika@redhat.com>
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=918152
Signed-off-by: Eli Mesika <emesika@redhat.com>