Blender Git Loki

Revert "Cycles: Cleanup: Don't use return on function returning void"

Not sure why exactly it is called a cleanup, the code was much more clear
and robust against possible missing return statements which are MANDATORY.

Missing return statement will:

- Cause two different BVH traversals to be run.

Not is happening currently, but if more BVH layouts are added, it will
become a problem.

- It is already causing assert() statements to fail, since functions are
no longer returning when they are supposed to.

If there is any measurable reason to keep this change, let me know.
Otherwise just stick to reliable/tested/robust code.

This reverts commit ba65f7093b39a8e5f1fb869cbc347fb810a05ab9.