Prevent using SetAmmo to set amNothing to anything.
--- a/hedgewars/uAmmos.pas Wed Oct 30 15:54:29 2013 -0400
+++ b/hedgewars/uAmmos.pas Thu Oct 31 10:46:52 2013 -0400
@@ -224,6 +224,7 @@
CurWeapon: PAmmo;
a: TAmmoType;
begin
+if ammo = amNothing then exit;
{$HINTS OFF}
FillChar(ammos, sizeof(ammos), 0);
{$HINTS ON}