close http connections

Running full tempest one might run out of file descriptors. httplib2
does not close the connection by default. This patch adds
connection:close header to every request, so that sockets won't be
hanging around.

fixes bug 1215804

Change-Id: Iea19936c45add98fc66588f623854e629cf448fb
diff --git a/tempest/services/object_storage/account_client.py b/tempest/services/object_storage/account_client.py
index 8defbbb..eb9910f 100644
--- a/tempest/services/object_storage/account_client.py
+++ b/tempest/services/object_storage/account_client.py
@@ -15,10 +15,10 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import httplib2
 import json
 import urllib
 
+from tempest.common import http
 from tempest.common.rest_client import RestClient
 from tempest import exceptions
 
@@ -108,7 +108,7 @@
 
     def request(self, method, url, headers=None, body=None):
         """A simple HTTP request interface."""
-        self.http_obj = httplib2.Http()
+        self.http_obj = http.ClosingHttp()
         if headers is None:
             headers = {}
         if self.base_url is None: