Remove unused code in api/compute/admin/test_quotas.py
Remove unused code in api/compute/admin/test_quotas.py

The 'tenants' variable is not used anywhere in the class, which should be
removed. Maybe it was ignored by someone when fixing something else.

Change-Id: I96eb4ff9590c6416c21d457e93075ddc74e5f3f3
Closes-bug: #1249804

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