Fixed problems in dispatcher, fixed testcase download error

deploy/entrypoint.sh

@@ -52,6 +52,7 @@ do
     python manage.py migrate --no-input &&
     python manage.py inituser --username=root --password=rootroot --action=create_super_admin &&
     echo "from options.options import SysOptions; SysOptions.judge_server_token='$JUDGE_SERVER_TOKEN'" | python manage.py shell &&
+    echo "from conf.models import JudgeServer; JudgeServer.objects.update(task_number=0)" | python manage.py shell &&
     break
     n=$(($n+1))
     echo "Failed to migrate, going to retry..."