Don't create ipset chain if corresponding security group has no member

[shihanzhang]

when a security group has bellow rule, it should not create ipset chain:
security group id is: fake_sgid, it has rule bellow:
{'direction': 'ingress', 'remote_group_id': 'fake_sgid2'}
but the security group:fake_sgid2 has no member, so when the port in security group:fake_sgid should not create corresponding ipset chain

root@devstack:/opt/stack/neutron# ipset list
Name: IPv409040f9f-cb86-4f72-a
Type: hash:ip
Revision: 2
Header: family inet hashsize 1024 maxelem 65536
Size in memory: 16520
References: 1
Members:
20.20.20.11

Name: IPv609040f9f-cb86-4f72-a
Type: hash:ip
Revision: 2
Header: family inet6 hashsize 1024 maxelem 65536
Size in memory: 16504
References: 1
Members:

because the security group:09040f9f-cb86-4f72-af74-4de4f2b86442 has no ipv6 member, so it should't create ipset chain:IPv609040f9f-cb86-4f72-a

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/121455
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=bf4a0199a73374d786e3a5bda770fd8545ebc4e9
Submitter: Jenkins
Branch: master

commit bf4a0199a73374d786e3a5bda770fd8545ebc4e9
Author: shihanzhang <email address hidden>
Date: Mon Sep 15 14:46:31 2014 +0800

    Don't create unused ipset chain

    when a security group don't have members, it should not create corresponding
    ipset chain.

    Change-Id: Ia04ffb3ac539c9a89a882e6dd91f373cb67c6f8b
    Closes-bug: #1369431