Update the cred's POST request handler to accept rowner update request.

Update the cred's POST request handler to accept rowner update request.

This update can handle the following payload :
   {"rowneruuid":"28516ab8-b35a-4726-a082-ee7685c33c8c"}

Change-Id: Ibee20c99ff05409fdaf44c2bdac209b871bde043
Signed-off-by: Chul Lee <chuls.lee@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/13993
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Jongmin Choi <jminl.choi@samsung.com>
Reviewed-by: Randeep Singh <randeep.s@samsung.com>
(cherry picked from commit 210bfd947e151abaa37c80fd1bdad0c5b731a768)
Reviewed-on: https://gerrit.iotivity.org/gerrit/14061