Fixed a session problem related to BT off/on for Android BLE.

Fixed a session problem related to BT off/on for Android BLE.

when BT turn off/on while device is connected,
BLE is not connected again.
so i have modified something like in below

- when BLE Disconnect event is called
  server have to start advertising again.
- the dataList of server/client have to destroy, when BT turn off.
- client have to start device scan again, when BT turn on.

Change-Id: I97b75d349a0e3205e221e1347d3f24ca23f4e139
Signed-off-by: jihwan.seo <jihwan.seo@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/2579
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Jaehong Jo <jaehong.jo@samsung.com>
Reviewed-by: Patrick Lankswert <patrick.lankswert@intel.com>