Happen an error when Gateway is requested from 'boto'

[yosukehara]

• An error log is as the follows:

Traceback (most recent call last):
  File "boto_test.py", line 39, in <module>
    s3_object = bucket.get_key("kanetayusaku01.txt")
  File "/usr/lib/python2.6/site-packages/boto-2.9.0_dev-py2.6.egg/boto/s3/bucket.py", line 169, in get_key
    key, resp = self._get_key_internal(key_name, headers, query_args_l)
  File "/usr/lib/python2.6/site-packages/boto-2.9.0_dev-py2.6.egg/boto/s3/bucket.py", line 196, in _get_key_internal
    k.size = int(response.getheader('content-length'))
ValueError: invalid literal for int() with base 10: '0, 15'

• Cause:
  • Reply incorrect 'content-length' (HTTP Header)

[mocchira]

One solution.
Returning a empty function will make codes pass the below point.
https://github.com/extend/cowboy/blob/master/src/cowboy_req.erl#L957