Manually update .dae to fix loading level after d56b156

Remove reference to Tile_Steel.material. The bug will happen again
next time the .blend is exported though, someone familiar with Blender
should fix it there.

level/geometry/demolevel.dae

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:b2f95d07e8b11af9c47335f906e649bb87f9b2c32b53c487a442b4640a9c2602
-size 336814248
+oid sha256:53439afdede93060cae01b9471bfda2fb472e8f3c67967539cc87a8e734ecdc3
+size 336814046