Ld414 invalid sound fix
This fixes Linedef type 414 crashing the game if an invalid sound number was supplied to it (this can happen if you, say, scrambled THZ2's textures cough), whether or not the "Repeat Midtexture" flag is checked.
This fixes Linedef type 414 crashing the game if an invalid sound number was supplied to it (this can happen if you, say, scrambled THZ2's textures cough), whether or not the "Repeat Midtexture" flag is checked.