Add some tests for the error path(s) in RBD cleanup_volumes()
Add some tests for the error path(s) in RBD cleanup_volumes()

This code depends on a module which is not always present, and thus is
a little tricky to test, given exceptions missing from that module. This
patch adds a few tests to validate that error path.

Change-Id: I03e9376d956c70ced60e5bee32b4598f7b34d0d5

JioCloud/nova_test_latest,sebrandon1/nova,watonyweng/nova,cernops/nova,CloudServer/nova,dims/nova,cloudbase/nova,bigswitch/nova,CloudServer/nova,adelina-t/nova,openstack/nova,hanlind/nova,openstack/nova,CEG-FYP-OpenStack/scheduler,mahak/nova,shail2810/nova,zaina/nova,openstack/nova,scripnichenko/nova,tealover/nova,isyippee/nova,NeCTAR-RC/nova,shail2810/nova,devendermishrajio/nova_test_latest,iuliat/nova,hanlind/nova,nikesh-mahalka/nova,fnordahl/nova,Stavitsky/nova,apporc/nova,ted-gould/nova,double12gzh/nova,takeshineshiro/nova,takeshineshiro/nova,jianghuaw/nova,zhimin711/nova,zhimin711/nova,rajalokan/nova,phenoxim/nova,NeCTAR-RC/nova,ted-gould/nova,gooddata/openstack-nova,felixma/nova,Juniper/nova,tudorvio/nova,vmturbo/nova,edulramirez/nova,BeyondTheClouds/nova,raildo/nova,edulramirez/nova,klmitch/nova,CEG-FYP-OpenStack/scheduler,JianyuWang/nova,rajalokan/nova,Juniper/nova,yatinkumbhare/openstack-nova,mikalstill/nova,scripnichenko/nova,dawnpower/nova,ruslanloman/nova,mandeepdhami/nova,mmnelemane/nova,belmiromoreira/nova,kimjaejoong/nova,sebrandon1/nova,joker946/nova,CCI-MOC/nova,bgxavier/nova,mahak/nova,akash1808/nova,MountainWei/nova,devendermishrajio/nova_test_latest,isyippee/nova,dawnpower/nova,varunarya10/nova_test_latest,akash1808/nova_test_latest,watonyweng/nova,devendermishrajio/nova,jianghuaw/nova,sebrandon1/nova,tudorvio/nova,TwinkleChawla/nova,Francis-Liu/animated-broccoli,yosshy/nova,alvarolopez/nova,zzicewind/nova,cyx1231st/nova,iuliat/nova,devendermishrajio/nova,Stavitsky/nova,blueboxgroup/nova,belmiromoreira/nova,CCI-MOC/nova,klmitch/nova,mikalstill/nova,eonpatapon/nova,akash1808/nova_test_latest,hanlind/nova,apporc/nova,kimjaejoong/nova,yosshy/nova,alexandrucoman/vbox-nova-driver,rahulunair/nova,petrutlucian94/nova,JioCloud/nova,gooddata/openstack-nova,alexandrucoman/vbox-nova-driver,thomasem/nova,rajalokan/nova,rahulunair/nova,nikesh-mahalka/nova,phenoxim/nova,cernops/nova,JioCloud/nova_test_latest,tealover/nova,j-carpentier/nova,thomasem/nova,barnsnake351/nova,dims/nova,petrutlucian94/nova,akash1808/nova,double12gzh/nova,BeyondTheClouds/nova,joker946/nova,varunarya10/nova_test_latest,cyx1231st/nova,raildo/nova,mahak/nova,noironetworks/nova,alaski/nova,cloudbase/nova,cernops/nova,cloudbase/nova,JianyuWang/nova,jeffrey4l/nova,yatinkumbhare/openstack-nova,Juniper/nova,MountainWei/nova,j-carpentier/nova,Tehsmash/nova,JioCloud/nova,ruslanloman/nova,whitepages/nova,rajalokan/nova,Juniper/nova,Tehsmash/nova,jeffrey4l/nova,rahulunair/nova,BeyondTheClouds/nova,bigswitch/nova,alvarolopez/nova,adelina-t/nova,LoHChina/nova,jianghuaw/nova,felixma/nova,vmturbo/nova,bgxavier/nova,mmnelemane/nova,mikalstill/nova,Francis-Liu/animated-broccoli,tangfeixiong/nova,zzicewind/nova,klmitch/nova,alaski/nova,noironetworks/nova,mandeepdhami/nova,barnsnake351/nova,blueboxgroup/nova,vmturbo/nova,gooddata/openstack-nova,tangfeixiong/nova,fnordahl/nova,zaina/nova,whitepages/nova,TwinkleChawla/nova,eonpatapon/nova,gooddata/openstack-nova,jianghuaw/nova,LoHChina/nova,klmitch/nova,vmturbo/nova