add test for zero weight region get_more_nodes
add test for zero weight region get_more_nodes

Change-Id: If537981e8deadd9c3528dcb30a15011c7781e334

openstack/swift,hurricanerix/swift,rackerlabs/swift,williamthegrey/swift,matthewoliver/swift,smerritt/swift,aerwin3/swift,openstack/swift,larsbutler/swift,williamthegrey/swift,hurricanerix/swift,hurricanerix/swift,smerritt/swift,revoer/keystone-8.0.0,openstack/swift,prashanthpai/swift,notmyname/swift,nadeemsyed/swift,rackerlabs/swift,matthewoliver/swift,notmyname/swift,tipabu/swift,matthewoliver/swift,smerritt/swift,clayg/swift,openstack/swift,psachin/swift,redbo/swift,tipabu/swift,tipabu/swift,psachin/swift,matthewoliver/swift,notmyname/swift,hurricanerix/swift,revoer/keystone-8.0.0,smerritt/swift,clayg/swift,larsbutler/swift,nadeemsyed/swift,psachin/swift,psachin/swift,redbo/swift,nadeemsyed/swift,nadeemsyed/swift,tipabu/swift,clayg/swift,swiftstack/swift,notmyname/swift,clayg/swift,swiftstack/swift,swiftstack/swift,prashanthpai/swift,aerwin3/swift