Fixed bug on MOT.

Fixed bug on MOT.

Previously, If owner(PT) tried DTLS handshake while MOT,
owner's uuid added as subowner.
This patch will fix it.

Change-Id: I6a062d89a630b5582330ac0461e72e62c1e08376
Signed-off-by: Chul Lee <chuls.lee@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/15209
Reviewed-by: Kevin Kane <kkane@microsoft.com>
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Greg Zaverucha <gregz@microsoft.com>
Reviewed-by: Jihun Ha <jihun.ha@samsung.com>
Reviewed-by: dongik Lee <dongik.lee@samsung.com>
Reviewed-by: Randeep Singh <randeep.s@samsung.com>
(cherry picked from commit 3f2a61fc379de75678628258e8a4473712d7a30b)
Reviewed-on: https://gerrit.iotivity.org/gerrit/15249