Added safety checks requested in code review.

Added safety checks requested in code review.

The requests can be found here:https://gerrit.iotivity.org/gerrit/#/c/363.

Change-Id: Ied1f370c7f836f22d2a3e5e00150bc974a7d35b7
Signed-off-by: Joseph Morrow <joseph.l.morrow@intel.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/366
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Erich Keane <erich.keane@intel.com>
Reviewed-by: Doug Hudson <douglas.hudson@intel.com>
Reviewed-by: Sudarshan Prasad <sudarshan.prasad@intel.com>