Fix error message in Pure driver with correct text
Fix error message in Pure driver with correct text

The error message was specifically mentioning the PureISCSIDriver but
now there is a PureFCDriver which could call the error message. This
change gets the name of the driver and uses that to ensure
the error message refers to the correct driver.

Closes-Bug: #1469523
Change-Id: Ib724073ea352dadfbe7ddcf4ee4ceedd5d2c7c41

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