util.pubsub: Factor out calling of broadcaster

This will simplify doing things along with broadcasting.

util/pubsub.lua

@@ -499,7 +499,7 @@ function service:delete(node, actor) --> ok, err
 	end
 
 	self.events.fire_event("node-deleted", { service = self, node = node, actor = actor });
-	self.config.broadcaster("delete", node, node_obj.subscribers, nil, actor, node_obj, self);
+	self:broadcast("delete", node, node_obj.subscribers, nil, actor, node_obj);
 	return true;
 end
 
@@ -562,10 +562,14 @@ function service:publish(node, actor, id, item, requested_config) --> ok, err
 	local event_data = { service = self, node = node, actor = actor, id = id, item = item };
 	self.events.fire_event("item-published/"..node, event_data);
 	self.events.fire_event("item-published", event_data);
-	self.config.broadcaster("items", node, node_obj.subscribers, item, actor, node_obj, self);
+	self:broadcast("items", node, node_obj.subscribers, item, actor, node_obj);
 	return true;
 end
 
+function service:broadcast(event, node, subscribers, item, actor, node_obj)
+	return self.config.broadcaster(event, node, subscribers, item, actor, node_obj, self);
+end
+
 function service:retract(node, actor, id, retract) --> ok, err
 	-- Access checking
 	if not self:may(node, actor, "retract") then
@@ -582,7 +586,7 @@ function service:retract(node, actor, id, retract) --> ok, err
 	end
 	self.events.fire_event("item-retracted", { service = self, node = node, actor = actor, id = id });
 	if retract then
-		self.config.broadcaster("retract", node, node_obj.subscribers, retract, actor, node_obj, self);
+		self:broadcast("retract", node, node_obj.subscribers, retract, actor, node_obj);
 	end
 	return true
 end
@@ -604,7 +608,7 @@ function service:purge(node, actor, notify) --> ok, err
 	end
 	self.events.fire_event("node-purged", { service = self, node = node, actor = actor });
 	if notify then
-		self.config.broadcaster("purge", node, node_obj.subscribers, nil, actor, node_obj, self);
+		self:broadcast("purge", node, node_obj.subscribers, nil, actor, node_obj);
 	end
 	return true
 end