Merge branch 's3' into py3

Author: dt3310321

qcloud_cos/cos_auth.py

@@ -43,6 +43,7 @@ def __call__(self, r):
         path = self._path
         uri_params = self._params
         headers = filter_headers(r.headers)
+        uri_params = dict([(k.lower(), v) for k, v in uri_params.items()])
         # reserved keywords in headers urlencode are -_.~, notice that / should be encoded and space should not be encoded to plus sign(+)
         headers = dict([(k.lower(), quote(to_bytes(v), '-_.~')) for k, v in headers.items()])  # headers中的key转换为小写，value进行encode
         uri_params = dict([(k.lower(), v) for k, v in uri_params.items()])