Swift object client: use urllib3 builtin support for chunked transfer

Urllib3 has native support for chunked encoding, so let's use this
instead of rolling our own. Less code to maintain, additional logging
and timing (thanks to our common RestClient). Yeah \O/.

Change-Id: I4a253a5cec0fc35009af25872239363625d417e3
diff --git a/tempest/lib/services/identity/v2/token_client.py b/tempest/lib/services/identity/v2/token_client.py
index 0350175..5716027 100644
--- a/tempest/lib/services/identity/v2/token_client.py
+++ b/tempest/lib/services/identity/v2/token_client.py
@@ -75,8 +75,12 @@
         return rest_client.ResponseBody(resp, body['access'])
 
     def request(self, method, url, extra_headers=False, headers=None,
-                body=None):
-        """A simple HTTP request interface."""
+                body=None, chunked=False):
+        """A simple HTTP request interface.
+
+        Note: this overloads the `request` method from the parent class and
+        thus must implement the same method signature.
+        """
         if headers is None:
             headers = self.get_headers(accept_type="json")
         elif extra_headers: