remove previous received data from ReceiveQueue for gatt server.

remove previous received data from ReceiveQueue for gatt server.

and modified to adjust destroy thread.

Change-Id: I39043ae19527160a4f76d808a4a8e8b70d055f8a
Signed-off-by: jihwan.seo <jihwan.seo@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/5843
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Ashok Babu Channa <ashok.channa@samsung.com>
(cherry picked from commit 2a7b046b63032c419db682fa11ed2ad2bf84081e)
Reviewed-on: https://gerrit.iotivity.org/gerrit/6135
Reviewed-by: Jon A. Cruz <jon@joncruz.org>