Do nothing more after radio initialization fails.

Thanks @thozza

libraries/MySensors/MySensor.cpp

@@ -102,7 +102,8 @@ void MySensor::begin(void (*_msgCallback)(const MyMessage &), uint8_t _nodeId, b
 
 	// Setup radio
 	if (!radio.init()) {
-		debug(PSTR("radio initialization failed!"));
+		debug(PSTR("radio init fail\n"));
+		while(1); // Nothing more we can do
 	}
 
 #ifdef MY_SIGNING_FEATURE