Check time to apply resource helper functions
Check time to apply resource helper functions

For many operations, the time it takes to apply resource helper
functions constitutes a significant percentage of the time spent
completing the total transaction.  A list port transaction may have to
process thirteen resource helpers, for example.  Introducing some timing
logging will allow us to get clarity on whether slowdowns that happen
from version to version are a result of these accumulated resource
extenders.

Change-Id: I4c8867bb21d01c7a70c1b015814ce5da62e23a50

openstack/neutron-lib,openstack/neutron-lib,openstack/neutron-lib,openstack/neutron-lib