Comment 2 for bug 1208964

So to clarify a bit, this is in the case of multiple back-ends. The config grouping should have probably been moved up the chain in to the main driver file if non-LVM drivers want to utilize the setting.

I'll move them up in to the main volume_opts config group, and folks can use them in other places (like block_device) if desired. Ideally we should probably make this configurable on each back-end independently at some point.