Use fixed ips for lbaas pool members

test_load_balancer_basic was using the floating ips.

Change-Id: Ia3cad4ecad7d86b28c57a377352fc1aad039418d
Closes-Bug: 1313121
Merge "Use fixed ips for lbaas pool members"
Merge branch 'master' of https://github.com/openstack/tempest