The wrapper doesn't do anything else than translating command
parameters, but it's load time is significant (because of python imports
mostly). Since we can't use python lvm API from non-root user anyway,
lets drop the wrapper and call `lvm` directly (or through sudo when
necessary).
This makes VM startup much faster - storage preparation is down from
over 10s to about 3s.
QubesOS/qubes-issues#2256