From: Brian Behlendorf <behlendorf1@llnl.gov>
Subject: [PATCH] linux have mlslabel

The ZFS update to onnv_141 brought with it support for a
security label attribute called mlslabel.  This feature
depends on zones to work correctly and thus I am disabling
it under Linux.  Equivilant functionality could be added
at some point in the future.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>