staging/lustre: remove linux/lustre_lib.h

Inline the only call to inode_init_lvb(). Move some definitions from
lustre/include/linux/lustre_lib.h to lustre/include/lustre_lib.h and
remove the first header.

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