We can never hit the end of mds_finish_open() with a non-zero error code

We can never hit the end of mds_finish_open() with a non-zero error code
because we exit early on error, so the mds_destroy_mfd() is bogus.  I left
RETURN(rc) in case things change in the future though.

We don't use request_body() anywhere inside mds_put_write_access(), but
since all of that code is just commented out I didn't do a real cleanup.
Just a bogus compiler warning fixed.