Remove identity race condition
Remove identity race condition

Remove race condition for identitiy tests. When running tests in
parallel, the XML and JSON classes causes duplicate error when
trying to create the same user. Changing test classes to avoid hardcoded
user names.

Change-Id: I133d774be64b374aca8def3d998927b3a87cea19
bp: speed-up-tempest

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