Add _create_volume to ThinLVMVolumeDriver

Previously, _create_volume from LVMISCSIDriver would be called
when the volume manager calls create_volume_from_snapshot.

Fixes bug: 1192601

Change-Id: I5cca287e8204c4647a5f09df961d9a76d0b38c42
Merge "Add _create_volume to ThinLVMVolumeDriver"