Fix mistake in new code

All I can say is it compiled in IDE 1.5.7...

RF24.h

@@ -52,8 +52,8 @@ private:
   bool dynamic_payloads_enabled; /**< Whether dynamic payloads are enabled. */
   uint8_t pipe0_reading_address[5]; /**< Last address set on pipe 0 for reading. */
   uint8_t addr_width; /**< The address width to use - 3,4 or 5 bytes. */
-  uint32_t lastAvailableCheck = 0; /**< Limits the amount of time betwen reading data, only when switching between modes */
-  boolean listeningStarted = 1; /**< Var for delaying available() after start listening */
+  uint32_t lastAvailableCheck; /**< Limits the amount of time between reading data, only when switching between modes */
+  boolean listeningStarted; /**< Var for delaying available() after start listening */
   
 public: