Add tests for rpcapi container methods
Add tests for rpcapi container methods

container_* methods in magnum/conductor/api.py were not covered

Closes-Bug: #1478682
Change-Id: I78b0fe9559bb85b798a19c997a5ff296495df3fb

sajuptpm/magnum,paulczar/magnum,Tennyson53/magnum,openstack/magnum,ffantast/magnum,openstack/magnum,ramielrowe/magnum,mjbrewer/testindex,mjbrewer/testindex,dimtruck/magnum,ArchiFleKs/magnum,jay-lau/magnum,eshijia/magnum,mjbrewer/testindex,Tennyson53/magnum,ffantast/magnum,Tennyson53/SUR,ChengTiesheng/magnum,ddepaoli3/magnum,annegentle/magnum,paulczar/magnum,ArchiFleKs/magnum,ramielrowe/magnum,sajuptpm/magnum,Alzon/SUR,Alzon/SUR,annegentle/magnum,ddepaoli3/magnum,eshijia/SUR,dimtruck/magnum,Tennyson53/SUR,eshijia/SUR,eshijia/magnum,ChengTiesheng/magnum