Fix RuntimeError while dictionary changed size during iteration
Fix RuntimeError while dictionary changed size during iteration

Change-Id: Ib10184dcc68387775908b646c90f2a952e2ad8cb
Co-Authored-By: zulijun <17ee28c58d84dcd80afd2743d4fd37ef63c3b7d9@unionpay.com>
Closes-Bug: 1598654

openstack/dragonflow,openstack/dragonflow,openstack/dragonflow