Add destroy_server to javelin2
Add destroy_server to javelin2

To make it easier to test and debug the create_server logic, add in the
destroy_server logic.

Change-Id: I97092a817db66b52b50eab26714e76c69e25e228

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