Correct typo in example, az was printed instead of ax

Author: sandeepmistry

libraries/CurieImu/examples/RawImuDataSerial/RawImuDataSerial.ino

@@ -137,7 +137,7 @@ void loop() {
 
   // display tab-separated accel/gyro x/y/z values
   Serial.print("a/g:\t");
-  Serial.print(az);
+  Serial.print(ax);
   Serial.print("\t");
   Serial.print(ay);
   Serial.print("\t");