Bug-fix & Internal API name change

Bug-fix & Internal API name change

1. Change Internal API Name
  - DeleteDeviceList() -> PMDeleteDeviceList()

2. Modify wrong log text in ownershiptransfermanager.c

3. Modify invalid return in DeviceDiscoveryHandler()
  - KEEP_TRANSACTION is used instead of ERROR and DELETE
    because this handler is waiting responses from multicast request

Change-Id: Id78b6d6ae91f6c92986ea26e9fc4d9cab3429fcb
Signed-off-by: Woochul Shim <woochul.shim@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/2391
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Randeep Singh <randeep.s@samsung.com>
Reviewed-by: Sachin Agrawal <sachin.agrawal@intel.com>