Remove all CONF values from RestClient

To moving RestClient to tempest-lib, this patch moves all CONF values
from RestClient to service clients. This patch adds TempestRestClient
which passes common CONF values for Tempest own values.

Change-Id: I3434061fd19de741e36b13bd3c458cf49fdfe783
diff --git a/tempest/services/messaging/json/messaging_client.py b/tempest/services/messaging/json/messaging_client.py
index 45534c7..c4c9f09 100644
--- a/tempest/services/messaging/json/messaging_client.py
+++ b/tempest/services/messaging/json/messaging_client.py
@@ -17,7 +17,7 @@
 import urllib
 
 from tempest.api_schema.response.messaging.v1 import queues as queues_schema
-from tempest.common import rest_client
+from tempest.common import service_client
 from tempest.common.utils import data_utils
 from tempest import config
 
@@ -25,7 +25,7 @@
 CONF = config.CONF
 
 
-class MessagingClientJSON(rest_client.RestClient):
+class MessagingClientJSON(service_client.ServiceClient):
 
     def __init__(self, auth_provider):
         super(MessagingClientJSON, self).__init__(