Netapp: fix multiple copies of cinder-volume
Netapp: fix multiple copies of cinder-volume

Various commands were failing when running multiple copies of
cinder-volume. This is due to storing an in memory copy of the luns
which may get updated in the backend by another cinder-volume. Fix
it by attempting to refresh the list of luns if one is not found
during a request.

Change-Id: Iecd1dc5146525d7240a09f71669a3ab239c488bd
Resolves-bug: #1367044

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