Fix rpc initialization of cinder-manager volume
Fix rpc initialization of cinder-manager volume

VolumeCommands.rpc_client is a property, so when the oslo.config argparser
introspect the class VolumeCommands at module loading time, it launch the
method. But the method depends on a initialized oslo.config.cfg.CONF object,
but this one is not yet initialized.

So don't use python property, to initialize the rpc_client correctly.

No test because of bug: #1398401

Change-Id: I2c2f0be6e7a9d0866f063d98e1f8213f62fb9f92
Closes-bug: #1398319

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