Add credential verification API and add logs for debugging.

Add credential verification API and add logs for debugging.

Patch #1 : Cherry-pick from master
Patch #2 : Modify the unittest of secure resource provider to remove error.

Change-Id: Ib23f99acd7e82fa1dc9fec42cc08c5179294a5eb
Signed-off-by: Chul Lee <chuls.lee@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/13477
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Kevin Kane <kkane@microsoft.com>
Reviewed-by: Dmitriy Zhuravlev <d.zhuravlev@samsung.com>
Reviewed-by: dongik Lee <dongik.lee@samsung.com>
Reviewed-by: Randeep Singh <randeep.s@samsung.com>
(cherry picked from commit 06b7dc1f47482238a3e4f987bc81ef23c417dfdd)
Reviewed-on: https://gerrit.iotivity.org/gerrit/13777