Use registry.receives decorator in neutron.db.availability_zone.router
Use registry.receives decorator in neutron.db.availability_zone.router

Switch to registry.receives decorator in neutron.db.availability_zone.router

Partial-Bug: #1668262
Change-Id: Ib4e34159bf71a749eddf945fb942f679da7bacd0

mahak/neutron,noironetworks/neutron,openstack/neutron,noironetworks/neutron,huntxu/neutron,mahak/neutron,eayunstack/neutron,openstack/neutron,openstack/neutron,mahak/neutron,eayunstack/neutron,huntxu/neutron