fix commander: set _was_landed before _land_detector topic update

Before _was_landed was set to the same value as the current
_land_detector.landed, thus outside of the update condition,
_was_landed && !_land_detector.landed could never be true.

This affects setting the home position, which is now set upon arming AND
upon takeoff.

src/modules/commander/Commander.cpp

@@ -1552,6 +1552,8 @@ Commander::run()
 
 		/* Update land detector */
 		if (_land_detector_sub.updated()) {
+			_was_landed = _land_detector.landed;
+			bool was_falling = _land_detector.freefall;
 			_land_detector_sub.copy(&_land_detector);
 
 			// Only take actions if armed
@@ -1573,15 +1575,12 @@ Commander::run()
 					}
 				}
 
-				if (_was_falling != _land_detector.freefall) {
+				if (was_falling != _land_detector.freefall) {
 					if (_land_detector.freefall) {
 						mavlink_and_console_log_info(&mavlink_log_pub, "Freefall detected");
 					}
 				}
 			}
-
-			_was_landed = _land_detector.landed;
-			_was_falling = _land_detector.freefall;
 		}
 
 

src/modules/commander/Commander.hpp

@@ -362,7 +362,6 @@ private:
 	bool		_status_changed{true};
 	bool		_arm_tune_played{false};
 	bool		_was_landed{true};
-	bool		_was_falling{false};
 	bool		_was_armed{false};
 	bool		_failsafe_old{false};	///< check which state machines for changes, clear "changed" flag
 	bool		_have_taken_off_since_arming{false};