Update the OTMContext management mechanism to improve the reliability of the OTM...

Update the OTMContext management mechanism to improve the reliability of the OTM process.

  1. Apply the list mechanism to manage the OTMContext.
    -> It replaces the global variables of OTMContext.

  2. Add the OCDoHandle member into OTMContext.
    -> In case of OTM process stopped before OTM process complete,
       unnecessary retransmission can be occur
       due to request is performed just before the OTM process stops.
       So we need to cancel this request to prevent retransmission.
       OCDoHandle will be used at this time.

  3. Add the device status of PDM to prevent duplicate OTM.
    -> Added PDM_DEVICE_INIT to prevent deplicate OTM.
       If device status is PDM_DEVICE_INIT, PT will skip OTM process of this device.

Change-Id: I74e200aa88a0c5016c065a518b75614bf4a3a7a8
Signed-off-by: Chul Lee <chuls.lee@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/13857
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Kevin Kane <kkane@microsoft.com>
Reviewed-by: Randeep Singh <randeep.s@samsung.com>