Copter: report terrain capability to GCS

ArduCopter/capabilities.cpp

@@ -10,4 +10,5 @@ void Copter::init_capabilities(void)
     hal.util->set_capabilities(MAV_PROTOCOL_CAPABILITY_SET_POSITION_TARGET_GLOBAL_INT);
     hal.util->set_capabilities(MAV_PROTOCOL_CAPABILITY_FLIGHT_TERMINATION);
     hal.util->set_capabilities(MAV_PROTOCOL_CAPABILITY_SET_ATTITUDE_TARGET);
+    hal.util->set_capabilities(MAV_PROTOCOL_CAPABILITY_TERRAIN);
 }