Cancel skill usage keeping on death (#5206)

Fixes #5058

Thanks to @admkakaroto and @qwerty7vp

src/map/pc.cpp

@@ -8323,6 +8323,11 @@ int pc_dead(struct map_session_data *sd,struct block_list *src)
 			duel_reject(sd->duel_invite, sd);
 	}
 
+	if( sd->skill_keep_using.tid != INVALID_TIMER ){
+		delete_timer( sd->skill_keep_using.tid, skill_keep_using );
+		sd->skill_keep_using.tid = INVALID_TIMER;
+	}
+
 	pc_close_npc(sd,2); //close npc if we were using one
 
 	/* e.g. not killed thru pc_damage */

src/map/skill.cpp

@@ -23141,6 +23141,7 @@ void do_init_skill(void)
 	add_timer_func_list(skill_castend_pos,"skill_castend_pos");
 	add_timer_func_list(skill_timerskill,"skill_timerskill");
 	add_timer_func_list(skill_blockpc_end, "skill_blockpc_end");
+	add_timer_func_list(skill_keep_using, "skill_keep_using");
 
 	add_timer_interval(gettick()+SKILLUNITTIMER_INTERVAL,skill_unit_timer,0,0,SKILLUNITTIMER_INTERVAL);
 }