xenapi: Fix test_rescue test to ensure assertions are valid
xenapi: Fix test_rescue test to ensure assertions are valid

The assertion in this test gathers the list of VDI references and then
checks if the string 'swap' isn't in the list. A VDI reference is a
UUID, so the string 'swap' will never match, even if the code being
tested is buggy.

Compare against an actual VDI reference. Also, add a positive assertion
to check that the root disk from the original VM is attached.

Change-Id: I3e3e9798ce63f2f260b7993620fde3749452bfc9
Closes-bug: 1290903

alexandrucoman/vbox-nova-driver,Metaswitch/calico-nova,fnordahl/nova,vmturbo/nova,devendermishrajio/nova,jianghuaw/nova,klmitch/nova,Tehsmash/nova,bigswitch/nova,apporc/nova,mahak/nova,mgagne/nova,sebrandon1/nova,MountainWei/nova,nikesh-mahalka/nova,phenoxim/nova,leilihh/nova,Metaswitch/calico-nova,scripnichenko/nova,CEG-FYP-OpenStack/scheduler,cloudbase/nova,JioCloud/nova_test_latest,leilihh/novaha,projectcalico/calico-nova,Francis-Liu/animated-broccoli,klmitch/nova,shahar-stratoscale/nova,JianyuWang/nova,j-carpentier/nova,bgxavier/nova,badock/nova,raildo/nova,CCI-MOC/nova,saleemjaveds/https-github.com-openstack-nova,hanlind/nova,belmiromoreira/nova,isyippee/nova,rahulunair/nova,thomasem/nova,virtualopensystems/nova,CCI-MOC/nova,berrange/nova,tudorvio/nova,dims/nova,jianghuaw/nova,cloudbase/nova,mmnelemane/nova,alvarolopez/nova,NeCTAR-RC/nova,devendermishrajio/nova,joker946/nova,klmitch/nova,rahulunair/nova,TwinkleChawla/nova,mgagne/nova,vmturbo/nova,yatinkumbhare/openstack-nova,Juniper/nova,tanglei528/nova,takeshineshiro/nova,BeyondTheClouds/nova,varunarya10/nova_test_latest,leilihh/novaha,yosshy/nova,jeffrey4l/nova,jeffrey4l/nova,kimjaejoong/nova,raildo/nova,phenoxim/nova,dawnpower/nova,tanglei528/nova,leilihh/nova,affo/nova,sebrandon1/nova,rajalokan/nova,apporc/nova,MountainWei/nova,Yusuke1987/openstack_template,cyx1231st/nova,fnordahl/nova,scripnichenko/nova,Stavitsky/nova,tangfeixiong/nova,CloudServer/nova,double12gzh/nova,silenceli/nova,edulramirez/nova,blueboxgroup/nova,Tehsmash/nova,tealover/nova,cloudbase/nova-virtualbox,BeyondTheClouds/nova,viggates/nova,felixma/nova,petrutlucian94/nova,TwinkleChawla/nova,JioCloud/nova,alexandrucoman/vbox-nova-driver,mahak/nova,virtualopensystems/nova,BeyondTheClouds/nova,thomasem/nova,iuliat/nova,double12gzh/nova,vmturbo/nova,viggates/nova,devendermishrajio/nova_test_latest,gooddata/openstack-nova,j-carpentier/nova,redhat-openstack/nova,shahar-stratoscale/nova,akash1808/nova,LoHChina/nova,hanlind/nova,tianweizhang/nova,openstack/nova,zhimin711/nova,akash1808/nova_test_latest,mandeepdhami/nova,alvarolopez/nova,openstack/nova,nikesh-mahalka/nova,berrange/nova,jianghuaw/nova,blueboxgroup/nova,maelnor/nova,zzicewind/nova,cyx1231st/nova,mikalstill/nova,watonyweng/nova,akash1808/nova_test_latest,belmiromoreira/nova,spring-week-topos/nova-week,JioCloud/nova,mikalstill/nova,ruslanloman/nova,CiscoSystems/nova,adelina-t/nova,CiscoSystems/nova,cloudbase/nova-virtualbox,Juniper/nova,whitepages/nova,rajalokan/nova,cernops/nova,rajalokan/nova,cernops/nova,gooddata/openstack-nova,eayunstack/nova,luogangyi/bcec-nova,zhimin711/nova,cloudbase/nova,LoHChina/nova,dims/nova,sebrandon1/nova,yatinkumbhare/openstack-nova,Francis-Liu/animated-broccoli,jianghuaw/nova,maelnor/nova,silenceli/nova,isyippee/nova,rahulunair/nova,watonyweng/nova,angdraug/nova,vladikr/nova_drafts,affo/nova,zaina/nova,devendermishrajio/nova_test_latest,whitepages/nova,hanlind/nova,tangfeixiong/nova,vmturbo/nova,badock/nova,cernops/nova,tudorvio/nova,eharney/nova,Juniper/nova,kimjaejoong/nova,Yusuke1987/openstack_template,takeshineshiro/nova,luogangyi/bcec-nova,akash1808/nova,eharney/nova,angdraug/nova,ruslanloman/nova,edulramirez/nova,saleemjaveds/https-github.com-openstack-nova,ted-gould/nova,ted-gould/nova,NeCTAR-RC/nova,joker946/nova,mmnelemane/nova,eonpatapon/nova,noironetworks/nova,shail2810/nova,Stavitsky/nova,spring-week-topos/nova-week,CEG-FYP-OpenStack/scheduler,bgxavier/nova,redhat-openstack/nova,mandeepdhami/nova,zaina/nova,tealover/nova,petrutlucian94/nova,orbitfp7/nova,zzicewind/nova,alaski/nova,tianweizhang/nova,projectcalico/calico-nova,Juniper/nova,rajalokan/nova,shail2810/nova,eayunstack/nova,noironetworks/nova,JioCloud/nova_test_latest,adelina-t/nova,klmitch/nova,barnsnake351/nova,bigswitch/nova,vladikr/nova_drafts,alaski/nova,varunarya10/nova_test_latest,orbitfp7/nova,felixma/nova,iuliat/nova,gooddata/openstack-nova,mikalstill/nova,gooddata/openstack-nova,yosshy/nova,dawnpower/nova,openstack/nova,mahak/nova,CloudServer/nova,JianyuWang/nova,eonpatapon/nova,barnsnake351/nova