Fix typo that causes NameError: global name 'exception' exception

Fixes bug #1089374

Change-Id: Ia5fd1f14c313bc11728328552dc8c1cf24c55374
diff --git a/tempest/common/rest_client.py b/tempest/common/rest_client.py
index f430f02..cf76642 100644
--- a/tempest/common/rest_client.py
+++ b/tempest/common/rest_client.py
@@ -214,7 +214,7 @@
         #http library does not do any action automatically
         if (resp.status in set((204, 205, 304)) or resp.status < 200 or
             method.upper() == 'HEAD') and body:
-            raise exception.ResponseWithNonEmptyBody(status=resp.status)
+            raise exceptions.ResponseWithNonEmptyBody(status=resp.status)
 
         #NOTE(afazekas):
         # If the HTTP Status Code is 205
@@ -228,7 +228,7 @@
         if (resp.status == 205 and
             0 != len(set(resp.keys()) - set(('status',)) -
             self.response_header_lc - self.general_header_lc)):
-            raise exception.ResponseWithEntity()
+            raise exceptions.ResponseWithEntity()
 
         #NOTE(afazekas)
         # Now the swift sometimes (delete not empty container)