Don't use dict.iterkeys()
Don't use dict.iterkeys()

Replace list(dict.iterkeys()) with list(dict). The call to iterkeys() is
useless and the iterkeys() method of dictionaries was removed in
Python 3

Change-Id: I16733643d4b92fe8134eec2549bbd679fe75fb9c

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