Cluster: don't propagate PUBLISH two times.

PUBLISH both published messages via Cluster bus and replication when
cluster was enabled, resulting in duplicated message in the slave.

src/pubsub.c

@@ -306,8 +306,10 @@ void punsubscribeCommand(redisClient *c) {
 
 void publishCommand(redisClient *c) {
     int receivers = pubsubPublishMessage(c->argv[1],c->argv[2]);
-    if (server.cluster_enabled) clusterPropagatePublish(c->argv[1],c->argv[2]);
-    forceCommandPropagation(c,REDIS_PROPAGATE_REPL);
+    if (server.cluster_enabled)
+        clusterPropagatePublish(c->argv[1],c->argv[2]);
+    else
+        forceCommandPropagation(c,REDIS_PROPAGATE_REPL);
     addReplyLongLong(c,receivers);
 }