Rover: remove unused distance_past_wp

APMrover2/Rover.h

@@ -368,7 +368,6 @@ private:
     // Loiter control
     uint16_t loiter_duration;       // How long we should loiter at the nav_waypoint (time in seconds)
     uint32_t loiter_start_time;     // How long have we been loitering - The start time in millis
-    float distance_past_wp;         // record the distance we have gone past the wp
     bool previously_reached_wp;     // set to true if we have EVER reached the waypoint
 
     // time that rudder/steering arming has been running

APMrover2/commands_logic.cpp

@@ -228,9 +228,6 @@ void Rover::do_nav_wp(const AP_Mission::Mission_Command& cmd, bool stay_active_a
     // this is the delay, stored in seconds
     loiter_duration = cmd.p1;
 
-    // this is the distance we travel past the waypoint - not there yet so 0 initially
-    distance_past_wp = 0;
-
     Location cmdloc = cmd.content.location;
     location_sanitize(current_loc, cmdloc);
     mode_auto.set_desired_location(cmdloc, stay_active_at_dest);