staging/lustre/ldlm: Remove ldlm_init/destroy_export()

These functions are used on the server-only, so get rid of them.
Also get rid of ldlm export hash operations and the struct.

Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>