Fixed incorrect task handle references for socket demo tasks

Author: alxhoff

src/async_sockets.c

@@ -185,6 +185,6 @@ int xCreateSocketTasks(void)
 
 void vDeleteSocketTasks(void)
 {
-    vTaskDelete(vUDPDemoTask);
-    vTaskDelete(vTCPDemoTask);
+    vTaskDelete(UDPDemoTask);
+    vTaskDelete(TCPDemoTask);
 }