fix chain depends

tests/test_recognize.py

@@ -2,7 +2,7 @@
 
 from unittest import TestCase
 
-from app.chain.common import CommonChain
+from app.chain.download import DownloadChain
 from app.chain.identify import IdentifyChain
 
 
@@ -16,5 +16,5 @@ class RecognizeTest(TestCase):
     def test_recognize(self):
         result = IdentifyChain().process(title="我和我的祖国 2019")
         self.assertEqual(str(result.media_info.tmdb_id), '612845')
-        exists = CommonChain().get_no_exists_info(result.media_info)
+        exists = DownloadChain().get_no_exists_info(result.media_info)
         self.assertTrue(exists[0])