Explore removing the index catalog SCons shims

With the completion of SERVER-29908, removing a circular dependency in our SCons libraries, we should revisit whether it is possible to get rid of the SCons shims in many index catalog files – like here, here and here!

This would make working with the index code much easier. There are also similar shims elsewhere in the catalog, but we have a lot of v4.2 work around indexes coming up.