core: update blank template origin type

currently the origin type for blank template is always RHEV
there is a config in the db for the default origin type of vms
so this patch uses this config to update blank template to the current
configuration, should be OVIRT in most cases.

Change-Id: Ib844899a61093c1c2b70a34adcddb0b9bca83b37
Signed-off-by: Omer Frenkel <ofrenkel@redhat.com>
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1057211