AckMsgs -> AckRequired in master:purge

Author: Francesco Mazzoli

src/rabbit_mirror_queue_master.erl

@@ -176,7 +176,7 @@ dropwhile(Pred, AckRequired,
     Len  = BQ:len(BQS),
     {Msgs, BQS1} = BQ:dropwhile(Pred, AckRequired, BQS),
     Len1 = BQ:len(BQS1),
-    ok = gm:broadcast(GM, {set_length, Len1, AckMsgs}),
+    ok = gm:broadcast(GM, {set_length, Len1, AckRequired}),
     Dropped = Len - Len1,
     SetDelivered1 = lists:max([0, SetDelivered - Dropped]),
     {Msgs, State #state { backing_queue_state = BQS1,