修复轨迹模式评卷后，普通模式回评未清除轨迹bug

stmms-biz/src/main/java/cn/com/qmth/stmms/biz/mark/service/Impl/TaskServiceImpl.java

@@ -248,12 +248,16 @@ public class TaskServiceImpl implements TaskService, ApplicationContextAware, In
                             LibraryStatus.MARKED));
 
             Map<String, List<TrackDTO>> trackMap = task.getTrackMap();
-            for (String questionNumber : trackMap.keySet()) {
-                trackService.deleteByStudentIdAndQuestionNumber(library.getStudentId(), questionNumber);
-                List<TrackDTO> list = trackMap.get(questionNumber);
-                for (TrackDTO dto : list) {
-                    trackService.save(dto.transform(library));
-                }
+            if(trackMap.isEmpty()){
+            	trackService.deleteByStudentId(library.getStudentId());
+            }else{
+            	for (String questionNumber : trackMap.keySet()) {
+            		trackService.deleteByStudentIdAndQuestionNumber(library.getStudentId(), questionNumber);
+            		List<TrackDTO> list = trackMap.get(questionNumber);
+            		for (TrackDTO dto : list) {
+            			trackService.save(dto.transform(library));
+            		}
+            	}
             }
 
             SpecialTagDTO[] tagList = task.getTagList();