Squash a warning

Author: michaelklishin

test/confirms_rejects_SUITE.erl

@@ -35,7 +35,7 @@ init_per_group(Group, Config) ->
       rabbit_ct_broker_helpers:setup_steps() ++
       rabbit_ct_client_helpers:setup_steps()).
 
-end_per_group(Group, Config) ->
+end_per_group(_Group, Config) ->
     rabbit_ct_helpers:run_steps(Config,
       rabbit_ct_client_helpers:teardown_steps() ++
       rabbit_ct_broker_helpers:teardown_steps()).
@@ -153,4 +153,4 @@ clean_acks_mailbox() ->
         {'basic.nack', _, _, _} -> clean_acks_mailbox()
     after
         1000 -> done
-    end.
+    end.