Tracker: mavlink component id to 1

The antenna tracker's system id (aka SYSID) should be different from
other vehicles but it's component id should be "1" like copter, plane
and rover.

AntennaTracker/system.pde

@@ -58,8 +58,6 @@ static void init_tracker()
     // GPS Initialization
     gps.init(NULL);
 
-    mavlink_system.compid = 4;
-
     ahrs.init();
     ahrs.set_fly_forward(false);