Add unit tests for api_version detection
Add unit tests for api_version detection

This commit adds unit tests for api version detection in
verify_tempest_config.

Partially implements bp: config-verification

Change-Id: I72d02db5e4a2dd83abe0e2eb4e4fed8b97c34e4c

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