Fix usage of registry.receives in Nova notifier
Fix usage of registry.receives in Nova notifier

Receives expects a list of events for each resource.

TrivalFix
Change-Id: I4a39f2e9d2f10639a209e7311fe44b94d369c5b1

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