Clean up Lustre client to facilitate pushing it into upstream Linux kernel. Need to split some server code dependencies from client to avoidmaking extensive server code changes.

There are some client-server shared modules that contain both client-side and server-side codes. For pushing client-side code to upstread linux kernel, we need to do some split/cleanup work.

This ticket is to split/cleanup obdclass/fid/fld's server-side handling from client-side.