completed the linkage between the endpoint mapper and the dcerpc

server endpoints. We can now successfully setup listening endpoints on
high ports, then use our endpoint mapper redirect incoming clients to
the right port.

also greatly cleanup the rpc over tcp session handling.

source/rpc_server/echo/rpc_echo.c

@@ -181,7 +181,7 @@ static const struct dcesrv_endpoint_ops rpc_echo_ops = {
 */
 void rpc_echo_init(struct dcesrv_context *dce)
 {
-	if (!dcesrv_endpoint_register(dce, &rpc_echo_ops)) {
+	if (!dcesrv_endpoint_register(dce, &rpc_echo_ops, &dcerpc_table_rpcecho)) {
 		DEBUG(1,("Failed to register rpcecho endpoint\n"));
 	}
 }