Fixed bugreport:6523 song duration exploit. credits to mkbu95! Thank you

git-svn-id: https://svn.code.sf.net/p/rathena/svn/trunk@16753 54d463be-8e91-2dee-dedb-b68131a5f0ec

src/map/skill.c

@@ -11825,13 +11825,10 @@ static int skill_unit_effect (struct block_list* bl, va_list ap)
 	skill_id = group->skill_id;
 
 	//Target-type check.
-	if( !(group->bl_flag&bl->type && battle_check_target(&unit->bl,bl,group->target_flag)>0) )
-	{
-		if( flag&4 && group->src_id == bl->id && group->state.song_dance&0x2 )
+	if( !(group->bl_flag&bl->type && battle_check_target(&unit->bl,bl,group->target_flag)>0) && (flag&4) ) {
+		if( group->state.song_dance&0x1 || (group->src_id == bl->id && group->state.song_dance&0x2) )
 			skill_unit_onleft(skill_id, bl, tick);//Ensemble check to terminate it.
-	}
-	else
-	{
+	} else {
 		if( flag&1 )
 			skill_unit_onplace(unit,bl,tick);
 		else