supervdsm: remove unused md_utils module

The method getMdDeviceUuidMap was added in commit b9b6ca2 without any
explanation on why it's needed. I couldn't find any trace of this being
ever used.

Change-Id: I18b0406418249225dd6107d1f419f879868a019d
Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/29823
Reviewed-by: Dan Kenigsberg <danken@redhat.com>