Increase count_since_commit on seek

When auto_commit is False this change enables an explicit call to
commit() to actually commit the offsets. Otherwise a consumer won't be
able to commit until at least one message is read.

Author: ecanzonieri

kafka/consumer/simple.py

@@ -214,8 +214,8 @@ def seek(self, offset, whence):
 
         # Reset queue and fetch offsets since they are invalid
         self.fetch_offsets = self.offsets.copy()
+        self.count_since_commit += 1
         if self.auto_commit:
-            self.count_since_commit += 1
             self.commit()
 
         self.queue = Queue()