options: Ignore check to find usd when we are building for Houdini.
options: Ignore check to find usd when we are building for Houdini.

We are using SideFx's USD when building for Houdini so we don't need
to find the usd version in the registry for that.

appleseedhq/cortex,appleseedhq/cortex,appleseedhq/cortex