Update time of last fusion event really only if fused

Except for the velpos fusion

EKF/airspeed_fusion.cpp

@@ -159,9 +159,6 @@ void Ekf::fuseAirspeed()
 			_innov_check_fail_status.flags.reject_airspeed = false;
 		}
 
-		// Airspeed measurement sample has passed check so record it
-		_time_last_arsp_fuse = _time_last_imu;
-
 		// apply covariance correction via P_new = (I -K*H)*P
 		// first calculate expression for KHP
 		// then calculate P - KHP
@@ -211,6 +208,7 @@ void Ekf::fuseAirspeed()
 			// apply the state corrections
 			fuse(Kfusion, _airspeed_innov);
 
+			_time_last_arsp_fuse = _time_last_imu;
 		}
 	}
 }