[Fixed] Bug when `missile` parameter is used for A_CustomBulletAttac

[Jekyll Grim Payne]

In g3d28006ed when missile parameter is used for A_CustomBulletAttack on a monster it results in a bug: when shooting, the monster will instantly move ahead a few units without interrupting the attack. It seems to happen only when spawnheight and spawnoffsetxy are also specified for the missile (perhaps only for specific offsets, I can't say, but when they're not specified it doesn't happen).

Attaching the demonstration file.

[Graf Zahl]

fixed