Add completion callback to IPCACloseHandle().

Add completion callback to IPCACloseHandle().

This addresses the scenario where the app needs to be certain when all
callbacks related to the handle it is closing are completed.

Change-Id: I75b211d477405be27c6c804bc89e529088aa1a90
Signed-off-by: Soemin Tjong <stjong@microsoft.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/18217
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Dan Mihai <Daniel.Mihai@microsoft.com>