staging/lustre/obdclass: Drop unused code from obdo.c

These functions are not even referenced in any header files anymore.

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