Remove LVM driver

Support of LVM driver is planned to be dropped as it is duplicates
functionality from Cinder. Default driver is Generic driver, that uses Cinder.

Changes:
- removed LVM driver
- removed related stuff to LVM driver

Partially implements blueprint remove-lvm-driver
Change-Id: If2df592db082fdc5d609a5ce644106fee7d0583d
Merge "Remove LVM driver"