fix bug https://github.com/AriaLyy/Aria/issues/81

Aria/src/main/java/com/arialyy/aria/core/download/downloader/DownloadGroupUtil.java

@@ -381,9 +381,8 @@ public class DownloadGroupUtil implements IDownloadUtil {
       if (mCompleteNum >= mTaskEntity.getEntity().getSubTask().size()) {
         closeTimer(false);
         mListener.onComplete();
-      }
+      } else if (mCompleteNum + mFailNum >= mActualTaskNum) {
         //如果子任务完成数量加上失败的数量和总任务数一致，则任务组停止下载
-      if (mCompleteNum + mFailNum >= mActualTaskNum) {
         closeTimer(false);
         mListener.onComplete();
       }