Add objects.register_all() to cinder-all command
Add objects.register_all() to cinder-all command

In cmd/all.py registration of objects was missing. This caused running
cinder-all command to raise exceptions about unknown objects. Following
commit fixes this problem.

Closes-Bug: 1484533
Change-Id: Id7686bc801aaea30c1f7f24209044311656fa4cd

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