L3G4200D: fix in the test example provided.

The test coded had a call to "wait_for_sample" that expected one
argument and 0 where provided.

libraries/AP_InertialSensor/examples/L3G4200D/L3G4200D.pde

@@ -167,7 +167,7 @@ void run_test()
     while( !hal.console->available() ) {
 
         // wait until we have a sample
-        ins.wait_for_sample();
+        ins.wait_for_sample(1000);
 
         // read samples from ins
         ins.update();