Fix network notifications of neutron bulk creation

When bulk creating ports, networks, subnets in neutron,
ceilometer-notification-agent will be broken and raise an KeyError.

Change-Id: Id5737f8ec8aa46561fe66bd56251d2a8d55f2548
Closes-Bug: #1317900
(cherry picked from commit bda44d592e02d95254d14819dbf5ffaeefa9f552)
Merge "Fix network notifications of neutron bulk creation" into stable/icehouse