Add Quota roll back for deallocate fix ip in nova-network

in nova-network, deallocate_fixed_ip function reserve quota
first then do deallocate operations if any operation failed,
the quota reserve operation need to be rollback.

Change-Id: If57d2b8a24b2f6ed3d90a1357e89782194df013c
Closes-Bug: #1284930
Merge "Add Quota roll back for deallocate fix ip in nova-network"