Fix a few bugs for LeftHand Grizzly

This patch fixes a few issues with the LH driver.
1) attach wasn't working because there was no host
created.
2) get_volume_stats didn't exist.
3) fixed the unit tests to work with the new config
access.

Bug 1062508
Bug 1150663

Change-Id: I6f80c3d5c70b64ca6496e50fedcb6b3ca0e2be43
Merge "Fix a few bugs for LeftHand Grizzly"