Blender Git Loki

Cycles: Remove hair support from volume BVH traversal

There are couple of reasons:

- Volume shader on hair does behave really weird anyway and it's
not something considered a bug really.

- Volume BVH traversal were only used by camera-in-volume check,
which doesn't really make sense to take hair into account since
it'll be rendered wrong anyway.

Such a removal makes both code easier to extend further (as in,
no need to worry about those traversal for hair bvh) and also
reduces stress on GPU compilers.