Mugsie (Graham Hayes) on IRC said that he abandoned the patch because the Neutron team required a unit test for this and he had no time to write one at this time..
<mugsie:#openstack-tr> no. its fine, it is a neutron reviewr going overboard as per usual so I still think it's worth adding to avoid problems. http://eavesdrop.openstack.org/irclogs/%23openstack-trove/%23openstack-trove.2016-07-25.log.html#t2016-07-25T17:54:23 -- If something's hard to do, then it's not worth doing. - Homer Simpson