nit: sudoers: drop unused executable

Should have been dropped by "Move prepare-vmchannel to supervdsm"
http://gerrit.ovirt.org/4242

Change-Id: Ib43ff714b243816e9746700efd0fbe8bd9a494e2
Signed-off-by: Dan Kenigsberg <danken@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/25250
Reviewed-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Reviewed-by: Vinzenz Feenstra <vfeenstr@redhat.com>
Reviewed-by: Yaniv Bronhaim <ybronhei@redhat.com>