Add missing EV_USE_ITEM15 cases

Add EV_USE_ITEM15 to cg_event.c and ai_dmq3.c for consistency.

code/cgame/cg_event.c

@@ -867,6 +867,10 @@ void CG_EntityEvent( centity_t *cent, vec3_t position ) {
 		DEBUGNAME("EV_USE_ITEM14");
 		CG_UseItem( cent );
 		break;
+	case EV_USE_ITEM15:
+		DEBUGNAME("EV_USE_ITEM15");
+		CG_UseItem( cent );
+		break;
 
 	//=================================================================
 

code/game/ai_dmq3.c

@@ -5009,6 +5009,7 @@ void BotCheckEvents(bot_state_t *bs, entityState_t *state) {
 		case EV_USE_ITEM12:
 		case EV_USE_ITEM13:
 		case EV_USE_ITEM14:
+		case EV_USE_ITEM15:
 			break;
 	}
 }