Add a shelve/unshelve scenario
Add a shelve/unshelve scenario

Current test of shelve/unshelve in api/compute/servers/test_server_actions
only checks the API. Nova Bug #1257594 shows that shelve was once not
reliable. This addition should prevent this bug from ever coming back.

Change-Id: Ie9c28e0f17e25f75ce435ac574244cd3c3c69c9a

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