staging/lustre/obdclass: Remove unused lprocfs_alloc/free_obd_stats

obd_stats in the form present were only used on the server,
so let's remove them from the client code
This also removes lprocfs_init_ops_stats helper.

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