Fixed Ceph backup librbd segfault
Fixed Ceph backup librbd segfault

Change-Id: I1a6b9935eb7da9fca5b572ea4823bae3def99ea0
Fixes: bug #1198271

phenoxim/cinder,dims/cinder,inkerra/cinder,scality/cinder,rickerc/cinder_audit,apporc/cinder,Paul-Ezell/cinder-1,bswartz/cinder,rakeshmi/cinder,scottdangelo/RemoveVolumeMangerLocks,NeCTAR-RC/cinder,takeshineshiro/cinder,JioCloud/cinder,tlakshman26/cinder-https-changes,scottdangelo/RemoveVolumeMangerLocks,abusse/cinder,takeshineshiro/cinder,rakeshmi/cinder,Datera/cinder,mahak/cinder,hguemar/cinder,winndows/cinder,alex8866/cinder,apporc/cinder,Akrog/cinder,ntt-sic/cinder,NetApp/cinder,NetApp/cinder,tlakshman26/cinder-https-changes,manojhirway/ExistingImagesOnNFS,nikesh-mahalka/cinder,redhat-openstack/cinder,ge0rgi/cinder,cloudbase/cinder,hguemar/cinder,Accelerite/cinder,cloudbau/cinder,julianwang/cinder,cloudbau/cinder,nexusriot/cinder,cloudbase/cinder,abusse/cinder,petrutlucian94/cinder,Nexenta/cinder,sasukeh/cinder,nikesh-mahalka/cinder,Accelerite/cinder,Paul-Ezell/cinder-1,julianwang/cinder,j-griffith/cinder,Akrog/cinder,Hybrid-Cloud/cinder,CloudServer/cinder,duhzecca/cinder,blueboxgroup/cinder,blueboxgroup/cinder,Hybrid-Cloud/cinder,dims/cinder,github-borat/cinder,scality/cinder,duhzecca/cinder,tlakshman26/cinder-bug-fix-volume-conversion-full,sasukeh/cinder,JioCloud/cinder,rickerc/cinder_audit,leilihh/cinder,eharney/cinder,ntt-sic/cinder,eharney/cinder,potsmaster/cinder,CloudServer/cinder,maelnor/cinder,j-griffith/cinder,spring-week-topos/cinder-week,bswartz/cinder,tlakshman26/cinder-bug-fix-volume-conversion-full,redhat-openstack/cinder,Datera/cinder,potsmaster/cinder,manojhirway/ExistingImagesOnNFS,leilihh/cinder,NeCTAR-RC/cinder,github-borat/cinder,inkerra/cinder,tlakshman26/cinder-new-branch,Thingee/cinder,Nexenta/cinder,nexusriot/cinder,openstack/cinder,tlakshman26/cinder-new-branch,phenoxim/cinder,mahak/cinder,spring-week-topos/cinder-week,winndows/cinder,alex8866/cinder,saeki-masaki/cinder,Thingee/cinder,petrutlucian94/cinder,openstack/cinder,saeki-masaki/cinder,maelnor/cinder,Thingee/cinder