check path first

pipeline/storage.py

@@ -74,7 +74,8 @@ class GZIPMixin(object):
             return
 
         for path in paths:
-            if path and not matches_patterns(path, self.gzip_patterns):
+            if path:
+                if not matches_patterns(path, self.gzip_patterns):
                     continue
                 original_file = self.open(path)
                 gzipped_path = "{0}.gz".format(path)