'Manages an existing VMAX Volume (import to Cinder).
Renames the Volume to match the expected name for the volume.
Also need to consider things like QoS, Emulation, account/tenant.
:param volume: the volume object
:param external_ref: the reference for the VMAX volume
:returns: model_update'

def manage_existing(self, volume, external_ref):

    return self.common.manage_existing(volume, external_ref)
