xenapi:live-block-migration - fix XML client test
xenapi:live-block-migration - fix XML client test

Fixes bug 1161356

KeyError: 'OS-EXT-SRV-ATTR:host' was raised while testing the live block
migration. This patch overrides the host detection in the XML client
case.

Change-Id: I90638d5b4a908171472611c4da5c5d915979ea6a

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