core: template can't be seen by user

The user_vm_template_permissions_view_base has a bug -
for the case user has permission on data center it returns the vmt_guid
as the entity id - but for templates - vmt_guid is zero guid.
What should be returned is the vm_guid (which is the template id)

Bug-Url: https://bugzilla.redhat.com/921450
Change-Id: I624eb8724da81bbffe0c4db973f67800c2593e3b
Signed-off-by: Yair Zaslavsky <yzaslavs@redhat.com>