ArduSub: removed set_blocking_writes_all calls

ArduSub/system.cpp

@@ -166,11 +166,6 @@ void Sub::init_ardupilot()
     g2.scripting.init();
 #endif // AP_SCRIPTING_ENABLED
 
-    // we don't want writes to the serial port to cause us to pause
-    // mid-flight, so set the serial ports non-blocking once we are
-    // ready to fly
-    serial_manager.set_blocking_writes_all(false);
-
     // enable CPU failsafe
     mainloop_failsafe_enable();