Make auto allocate cleanup retry
Make auto allocate cleanup retry

This adds a retry decorator to the auto allocate cleanup logic
so it can handle retriable errors during cleanup. It also adds
catches for notfound errors to make the function idempotent so
it works on retries.

Change-Id: I3d62af3018fb834ec85771d8bc8e7379cc80b72a
Closes-Bug: #1615710

sebrandon1/neutron,eayunstack/neutron,igor-toga/local-snat,eayunstack/neutron,huntxu/neutron,cloudbase/neutron,openstack/neutron,noironetworks/neutron,mahak/neutron,mahak/neutron,igor-toga/local-snat,noironetworks/neutron,mahak/neutron,cloudbase/neutron,openstack/neutron,sebrandon1/neutron,openstack/neutron,huntxu/neutron