Update server_playerDied.sqf

I've been trying to debug an issue with my kill messages recently, this wasn't the cause of the problem but seems to me this change needs making too? 

_victim is not declared until line 11 

The errors I get look like this, which was what lead me to look at that code initially... 

14:43:03 Error in expression <ect 3;
_playerName = 	name _newObject;

_victim removeAllEventHandlers "MPHit";
>
14:43:03   Error position: <_victim removeAllEventHandlers "MPHit";
>
14:43:03   Error Undefined variable in expression: _victim
14:43:03 File z\addons\dayz_server\compile\server_playerDied.sqf, line 11