Fixed compile errors from bad commits.

Marlin/Configuration.h

 // 21 = Elefu Ra Board (v3)
 
 #ifndef MOTHERBOARD
-//#define MOTHERBOARD 7
+#define MOTHERBOARD 7
 #endif
 
 // Define this to set a custom name for your generic Mendel,

Marlin/Marlin.h

    #else
          #define MYSERIAL Serial
    #endif // BTENABLED
+#else
+  #define MYSERIAL MSerial
 #endif
 
 #define SERIAL_PROTOCOL(x) (MYSERIAL.print(x))

Marlin/language.h

 	#else
 		#define MACHINE_NAME "Mendel"
 	#endif
-	#ifndef MACHINE_UUID
-		#define MACHINE_UUID "00000000-0000-0000-0000-000000000000"
-	#endif
+
 	#define FIRMWARE_URL "http://www.mendel-parts.com"
 #endif
 
+#ifndef MACHINE_UUID
+   #define MACHINE_UUID "00000000-0000-0000-0000-000000000000"
+#endif
+
 #define STRINGIFY_(n) #n
 #define STRINGIFY(n) STRINGIFY_(n)