Add ipaddress in manila requirements
Add ipaddress in manila requirements

The ipaddress module required by recent ipv6 work:
https://review.openstack.org/#/c/312321/80/manila/api/common.py

Change-Id: Idd0014d898d5468922625e62f9e649936dc05e35

bswartz/manila,openstack/manila,bswartz/manila,openstack/manila