Fix print name of ResponseBody object

Change-Id: I80c7f1d1013bd2b1650149cb8bd5cf5d3088ccfc
diff --git a/tempest/common/rest_client.py b/tempest/common/rest_client.py
index d271719..f4fe92b 100644
--- a/tempest/common/rest_client.py
+++ b/tempest/common/rest_client.py
@@ -66,7 +66,7 @@
 
     def __str__(self):
         body = super.__str__(self)
-        return "request: %s\nBody: %s" % (self.response, body)
+        return "response: %s\nBody: %s" % (self.response, body)
 
 
 class RestClient(object):