fix warnings

Change-Id: Ib5b0d4719001afffb231261b56e729aaa8714614
Reviewed-on: http://gerrit.aldebaran.lan/49892
Tested-by: gerrit
Reviewed-by: pdaouadi <pdaouadi@aldebaran-robotics.com>
Tested-by: pdaouadi <pdaouadi@aldebaran-robotics.com>