Don't list service-instances when ports don't have any interface

[Hampapur Ajay]

Following snippet ends up picking up all SIs when si_ids is empty list, don't list if si_ids is empty list.

https://github.com/Juniper/contrail-controller/blob/master/src/config/vnc_openstack/vnc_openstack/neutron_plugin_db.py#L706

        # Read only SIs associated with vm_objs
        si_ids = [si_ref['uuid']
                    for vm_obj in vm_objs
                    for si_ref in vm_obj.get_service_instance_refs() or []]
        si_objs = self._vnc_lib.service_instances_list(
            obj_uuids=si_ids, fields=['logical_router_back_refs'], detail=True)
        memo_req['service-instances'] = dict((si_obj.uuid, si_obj) for si_obj in si_objs)

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/23485
Submitter: Hampapur Ajay (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/23485
Committed: http://github.org/Juniper/contrail-controller/commit/5b334acf9f7cbd57581a70023cec3e390b84b15b
Submitter: Zuul
Branch: master

commit 5b334acf9f7cbd57581a70023cec3e390b84b15b
Author: Hampapur Ajay <email address hidden>
Date: Fri Aug 19 16:28:55 2016 -0700

Don't invoke vnc_lib.service_instances_list() if there is no
service instance to read.

Change-Id: I271ea17fa36b16e0d68af2b73cd6977a9093bc51
Closes-Bug: 1615159

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/23525
Submitter: Hampapur Ajay (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Review in progress for https://review.opencontrail.org/23526
Submitter: Hampapur Ajay (<email address hidden>)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/23526
Committed: http://github.org/Juniper/contrail-controller/commit/2072ac0749fb111d99c5813fdd0268e030ddf3c3
Submitter: Zuul
Branch: R3.0

commit 2072ac0749fb111d99c5813fdd0268e030ddf3c3
Author: Hampapur Ajay <email address hidden>
Date: Fri Aug 19 16:28:55 2016 -0700

Don't invoke vnc_lib.service_instances_list() if there is no
service instance to read.

Change-Id: I271ea17fa36b16e0d68af2b73cd6977a9093bc51
Closes-Bug: 1615159
(cherry picked from commit 5b334acf9f7cbd57581a70023cec3e390b84b15b)

[OpenContrail Admin (ci-admin-f)]

Reviewed: https://review.opencontrail.org/23525
Committed: http://github.org/Juniper/contrail-controller/commit/2cc5d3a86f392729d49ceae0942f3ab08c7c1307
Submitter: Zuul
Branch: R3.1

commit 2cc5d3a86f392729d49ceae0942f3ab08c7c1307
Author: Hampapur Ajay <email address hidden>
Date: Fri Aug 19 16:28:55 2016 -0700

Don't invoke vnc_lib.service_instances_list() if there is no
service instance to read.

Change-Id: I271ea17fa36b16e0d68af2b73cd6977a9093bc51
Closes-Bug: 1615159
(cherry picked from commit 5b334acf9f7cbd57581a70023cec3e390b84b15b)