Fix MY_SIGNING_REQUEST_SIGNATURES compile error

http://forum.mysensors.org/topic/1021/security-introducing-signing-support-to-mysensors/176

libraries/MySensors/MySensor.h

@@ -28,8 +28,10 @@
 	#define MY_IS_GATEWAY (true)
 	#define MY_NODE_TYPE "gateway"
 #elif defined(MY_REPEATER_FEATURE)
+	#define MY_IS_GATEWAY (false)
 	#define MY_NODE_TYPE "repeater"
 #else
+	#define MY_IS_GATEWAY (false)
 	#define MY_NODE_TYPE "sensor"
 #endif
 

libraries/MySensors/core/MyTransport.cpp

@@ -90,7 +90,7 @@ inline void transportProcess() {
 		#ifdef MY_SIGNING_REQUEST_SIGNATURES
 
 			if ((!MY_IS_GATEWAY || DO_SIGN(sender)) &&
-				destination == nc.nodeId &&
+				destination == _nc.nodeId &&
 				mGetLength(_msg) &&
 				!mGetAck(_msg) &&
 				(mGetCommand(_msg) != C_INTERNAL ||