Correctly call client inits from test_multi_backend
Correctly call client inits from test_multi_backend

This commit fixes the client init calls in setUpClass for
test_mult_backend. Since this doesn't run in the gate it slipped through
the massive config refactor.

Closes-Bug: #1276215

Change-Id: Ibcd521a5b5c3f4d755387b29ee73dcc042c44fa0

CiscoSystems/tempest,danielmellado/tempest,FujitsuEnablingSoftwareTechnologyGmbH/tempest,queria/my-tempest,dkalashnik/tempest,NexusIS/tempest,Tesora/tesora-tempest,flyingfish007/tempest,yamt/tempest,vedujoshi/os_tempest,Lilywei123/tempest,hpcloud-mon/tempest,Juraci/tempest,pczerkas/tempest,CiscoSystems/tempest,yamt/tempest,vedujoshi/tempest,pandeyop/tempest,roopali8/tempest,manasi24/tempest,jaspreetw/tempest,jamielennox/tempest,nunogt/tempest,hayderimran7/tempest,bigswitch/tempest,varunarya10/tempest,Vaidyanath/tempest,izadorozhna/tempest,izadorozhna/tempest,cloudbase/lis-tempest,sebrandon1/tempest,afaheem88/tempest,eggmaster/tempest,Tesora/tesora-tempest,alinbalutoiu/tempest,tudorvio/tempest,nunogt/tempest,afaheem88/tempest_neutron,rzarzynski/tempest,zsoltdudas/lis-tempest,hpcloud-mon/tempest,xbezdick/tempest,afaheem88/tempest,ntymtsiv/tempest,redhat-cip/tempest,flyingfish007/tempest,queria/my-tempest,neerja28/Tempest,Juraci/tempest,Lilywei123/tempest,tonyli71/tempest,ntymtsiv/tempest,vedujoshi/tempest,masayukig/tempest,FujitsuEnablingSoftwareTechnologyGmbH/tempest,Mirantis/tempest,vmahuli/tempest,jaspreetw/tempest,alinbalutoiu/tempest,neerja28/Tempest,cisco-openstack/tempest,cisco-openstack/tempest,cloudbase/lis-tempest,redhat-cip/tempest,akash1808/tempest,pczerkas/tempest,tudorvio/tempest,JioCloud/tempest,JioCloud/tempest,dkalashnik/tempest,roopali8/tempest,afaheem88/tempest_neutron,manasi24/jiocloud-tempest-qatempest,NexusIS/tempest,hayderimran7/tempest,rakeshmi/tempest,manasi24/jiocloud-tempest-qatempest,vmahuli/tempest,pandeyop/tempest,openstack/tempest,sebrandon1/tempest,tonyli71/tempest,Juniper/tempest,ebagdasa/tempest,LIS/lis-tempest,manasi24/tempest,eggmaster/tempest,rzarzynski/tempest,xbezdick/tempest,Vaidyanath/tempest,openstack/tempest,bigswitch/tempest,LIS/lis-tempest,akash1808/tempest,zsoltdudas/lis-tempest,Mirantis/tempest,danielmellado/tempest,jamielennox/tempest,rakeshmi/tempest,vedujoshi/os_tempest,ebagdasa/tempest,Juniper/tempest,masayukig/tempest,varunarya10/tempest