Fix a spec that caused two warnings

Author: essen

src/lager_exchange_backend.erl

@@ -165,8 +165,8 @@ handle_log_event({log, Message},
                                  headers      = Headers},
             Body = rabbit_data_coercion:to_binary(Formatter:format(Message, FormatConfig)),
             case rabbit_basic:publish(LogExch, RoutingKey, AmqpMsg, Body) of
-                {ok, _DeliveredQPids} -> ok;
-                {error, not_found}    -> ok
+                ok                 -> ok;
+                {error, not_found} -> ok
             end,
             {ok, State};
         false ->

src/rabbit_basic.erl

@@ -29,7 +29,7 @@
 -type properties_input() ::
         rabbit_framing:amqp_property_record() | [{atom(), any()}].
 -type publish_result() ::
-        {ok, [pid()]} | rabbit_types:error('not_found').
+        ok | rabbit_types:error('not_found').
 -type header() :: any().
 -type headers() :: rabbit_framing:amqp_table() | 'undefined'.
 
@@ -107,8 +107,7 @@ publish(Delivery = #delivery{
 
 publish(X, Delivery) ->
     Qs = rabbit_amqqueue:lookup(rabbit_exchange:route(X, Delivery)),
-    DeliveredQPids = rabbit_amqqueue:deliver(Qs, Delivery),
-    {ok, DeliveredQPids}.
+    rabbit_amqqueue:deliver(Qs, Delivery).
 
 delivery(Mandatory, Confirm, Message, MsgSeqNo) ->
     #delivery{mandatory = Mandatory, confirm = Confirm, sender = self(),

src/rabbit_trace.erl

@@ -102,7 +102,7 @@ trace(#exchange{name = Name}, #basic_message{exchange_name = Name},
     ok;
 trace(X, Msg = #basic_message{content = #content{payload_fragments_rev = PFR}},
       RKPrefix, RKSuffix, Extra) ->
-    {ok, _} = rabbit_basic:publish(
+    ok = rabbit_basic:publish(
                 X, <<RKPrefix/binary, ".", RKSuffix/binary>>,
                 #'P_basic'{headers = msg_to_table(Msg) ++ Extra}, PFR),
     ok.