Fix incorrect fact usage for grid entry location

src/MissionManager/SurveyMissionItem.cc

@@ -224,7 +224,7 @@ void SurveyMissionItem::save(QJsonArray&  missionItems)
     gridObject[_jsonGridAltitudeRelativeKey] =  _gridAltitudeRelativeFact.rawValue().toBool();
     gridObject[_jsonGridAngleKey] =             _gridAngleFact.rawValue().toDouble();
     gridObject[_jsonGridSpacingKey] =           _gridSpacingFact.rawValue().toDouble();
-    gridObject[_jsonGridEntryLocationKey] =           _gridSpacingFact.rawValue().toDouble();
+    gridObject[_jsonGridEntryLocationKey] =     _gridEntryLocationFact.rawValue().toDouble();
     gridObject[_jsonTurnaroundDistKey] =        _turnaroundDistFact.rawValue().toDouble();
 
     saveObject[_jsonGridObjectKey] = gridObject;