resource: Fix cppcheck issues in resource/csdk/security/ dir

resource: Fix cppcheck issues in resource/csdk/security/ dir

This patch fixes the "(error) Possible null pointer dereference:" issues
reported by cppcheck tool in resource/csdk/security/ directory.

Change-Id: I36c41312fe3d78edd43c6c505b875ecbb6ba0dfa
Signed-off-by: Ravi Nanjundappa <nravi.n@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/2905
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Jon A. Cruz <jonc@osg.samsung.com>
Reviewed-by: Shilpa Sodani <shilpa.a.sodani@intel.com>
Reviewed-by: Madan Lanka <lanka.madan@samsung.com>