staging/lustre/obdecho: Remove unused ioctls

Remove long unused ECHO_IOC_GET_STRIPE, ECHO_IOC_SET_STRIPE,
ECHO_IOC_ENQUEUE and ECHO_IOC_CANCEL ioctls.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>