One Eggscalibur fix

Use mobj->watertop instead of mobj->spawnpoint->z. CEZ3 is far from fixed in multiplayer, but this is still one less thing to worry about.

Considering MI's other fixes, I'd like to test whether together they keep CEZ3 in lockstep. (Unfortunately, uni coursework prevents my involvement in srbmatters right now. :v )

Do we want this simple variable replacement in in .17 or what?

+1 Tested for myself and all seems to be fine; haven't enountered CEZ3 desyncing at all yet even

Status changed to merged

mentioned in commit 45fdfd9f