S3FS tests fail with non-us locale
```python
diff --git a/pandas/tests/io/parser/test_network.py b/pandas/tests/io/parser/test_network.py
index a7cc3ad98..2b728c03d 100644
--- a/pandas/tests/io/parser/test_network.py
+++ b/pandas/tests/io/parser/test_network.py
@@ -59,6 +59,9 @@ class TestS3(object):
 
     def test_parse_public_s3_bucket(self, tips_df):
         pytest.importorskip('s3fs')
+        import locale
+
+        locale.setlocale(locale.LC_ALL, "zh_CN.UTF-8")
         # more of an integration test due to the not-public contents portion
         # can probably mock this though.
         for ext, comp in [('', None), ('.gz', 'gzip'), ('.bz2', 'bz2')]:
```

fails with

```python
pytest pandas/tests/io/parser/test_network.py -k test_parse_public_s3_bucket --tb=short -x
==================================================================== test session starts =====================================================================
platform darwin -- Python 3.6.5, pytest-3.7.1, py-1.5.3, pluggy-0.7.1
rootdir: /Users/taugspurger/sandbox/pandas, inifile: setup.cfg
plugins: xonsh-0.6.2, xdist-1.15.0, rerunfailures-2.2, repeat-0.4.1, cov-2.5.1, annotate-1.0.0, hypothesis-3.44.26
collected 28 items / 22 deselected

pandas/tests/io/parser/test_network.py F

========================================================================== FAILURES ==========================================================================
_____________________________________________________________ TestS3.test_parse_public_s3_bucket _____________________________________________________________
../../Envs/pandas-dev/lib/python3.6/site-packages/botocore/utils.py:367: in parse_timestamp
    return dateutil.parser.parse(value, tzinfos={'GMT': tzutc()})
../../Envs/pandas-dev/lib/python3.6/site-packages/dateutil/parser.py:1182: in parse
    return DEFAULTPARSER.parse(timestr, **kwargs)
../../Envs/pandas-dev/lib/python3.6/site-packages/dateutil/parser.py:559: in parse
    raise ValueError("Unknown string format")
E   ValueError: Unknown string format

During handling of the above exception, another exception occurred:
pandas/tests/io/parser/test_network.py:69: in test_parse_public_s3_bucket
    ext, compression=comp)
pandas/io/parsers.py:704: in parser_f
    return _read(filepath_or_buffer, kwds)
pandas/io/parsers.py:433: in _read
    filepath_or_buffer, encoding, compression)
pandas/io/common.py:216: in get_filepath_or_buffer
    mode=mode)
pandas/io/s3.py:29: in get_filepath_or_buffer
    filepath_or_buffer = fs.open(_strip_schema(filepath_or_buffer), mode)
../../Envs/pandas-dev/lib/python3.6/site-packages/s3fs/core.py:299: in open
    fill_cache=fill_cache, s3_additional_kwargs=kw)
../../Envs/pandas-dev/lib/python3.6/site-packages/s3fs/core.py:1017: in __init__
    self.size = self.info()['Size']
../../Envs/pandas-dev/lib/python3.6/site-packages/s3fs/core.py:1027: in info
    return self.s3.info(self.path, **kwargs)
../../Envs/pandas-dev/lib/python3.6/site-packages/s3fs/core.py:406: in info
    Key=key, **self.req_kw)
../../Envs/pandas-dev/lib/python3.6/site-packages/s3fs/core.py:164: in _call_s3
    return method(**additional_kwargs)
../../Envs/pandas-dev/lib/python3.6/site-packages/botocore/client.py:314: in _api_call
    return self._make_api_call(operation_name, kwargs)
../../Envs/pandas-dev/lib/python3.6/site-packages/botocore/client.py:599: in _make_api_call
    operation_model, request_dict)
../../Envs/pandas-dev/lib/python3.6/site-packages/botocore/endpoint.py:148: in make_request
    return self._send_request(request_dict, operation_model)
../../Envs/pandas-dev/lib/python3.6/site-packages/botocore/endpoint.py:175: in _send_request
    request, operation_model, attempts)
../../Envs/pandas-dev/lib/python3.6/site-packages/botocore/endpoint.py:256: in _get_response
    response_dict, operation_model.output_shape)
../../Envs/pandas-dev/lib/python3.6/site-packages/botocore/parsers.py:242: in parse
    parsed = self._do_parse(response, shape)
../../Envs/pandas-dev/lib/python3.6/site-packages/botocore/parsers.py:728: in _do_parse
    member_shapes, final_parsed)
../../Envs/pandas-dev/lib/python3.6/site-packages/botocore/parsers.py:789: in _parse_non_payload_attrs
    member_shape, headers[header_name])
../../Envs/pandas-dev/lib/python3.6/site-packages/botocore/parsers.py:295: in _parse_shape
    return handler(shape, node)
../../Envs/pandas-dev/lib/python3.6/site-packages/botocore/parsers.py:175: in _get_text_content
    return func(self, shape, text)
../../Envs/pandas-dev/lib/python3.6/site-packages/botocore/parsers.py:450: in _handle_timestamp
    return self._timestamp_parser(text)
../../Envs/pandas-dev/lib/python3.6/site-packages/botocore/utils.py:369: in parse_timestamp
    raise ValueError('Invalid timestamp "%s": %s' % (value, e))
E   ValueError: Invalid timestamp "二, 14  8 2018 12:22:47 GMT": Unknown string format
```

cc @martindurant, at a glance, it looks like s3fs is fine here. All the timestamp-based stuff that boto seems to be chocking on is done within boto itself, AFAICT...