staging/lustre/ldlm: Remove unused ldlm_cli_enqueue_local()

This is only used on the server.
Also while we are at it, remove unused prototypes for
ldlm_server_ast and ldlm_handle_enqueue0() that are not
defined anywhere

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