Ceph Multibackend changes

The plain Encryptor provider is not support on ceph backends, the
test test_encrypted_cinder_volumes_cryptsetup fails on:
cinder.exception.VolumeDriverException: Volume driver reported an error:
Provider plain not supported.
This comes from [1] which is called in [2]. The Plain provider will be deprecated
in future completely.

[1] https://opendev.org/openstack/cinder/src/branch/master/cinder/volume/volume_utils.py#L1195
[2] https://opendev.org/openstack/cinder/src/branch/master/cinder/volume/drivers/rbd.py#L877

Change-Id: Ib6290ed1ad5779e4e6fed449f3335dbdada42f0d

Related-Prod: PRODX-3456
Change-Id: I779f9bfade6c4740aef8bef0fbe0385081be2ba1
1 file changed