Remove build warnings

Remove build warnings

Change-Id: Ib22fda47f5e843bc753966c085942014d70d4922
Signed-off-by: Jaewook Jung <jw0213.jung@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/19949
Reviewed-by: Phil Coval <philippe.coval@osg.samsung.com>
Reviewed-by: Glen Youngjin Kim <glen.kim@samsung.com>
Reviewed-by: Hyuna Jo <hyuna0213.jo@samsung.com>
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Dan Mihai <Daniel.Mihai@microsoft.com>
Reviewed-by: Todd Malsbary <todd.malsbary@intel.com>
Reviewed-by: Dave Thaler <dthaler@microsoft.com>
Reviewed-by: Uze Choi <uzchoi@samsung.com>
Reviewed-by: Ashok Babu Channa <ashok.channa@samsung.com>