Port block_device driver to use new driver model
Port block_device driver to use new driver model

Use new ABCmeta driver model for block_device driver.

Change-Id: I8af975f58909352a105182a59ff777affec75e35
Implements: blueprint abc-driver-update

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