gemfile: Added netaddr package
gemfile: Added netaddr package

netaddr dependency is required for change-id:
Iffb0af32753708decb8d2b60f1075b66f7520553,
netaddr works effectively with CIDR, subnetting and etc.

Change-Id: I802280e4e2912c9aed1c10d519ead84b1f22f900

openstack/puppet-openstack-integration,openstack/puppet-openstack-integration,openstack/puppet-openstack-integration