staging/lustre/llite: remove llite/*_cookiesize proc files

Since Lustre 2.5, cookiesize is unused on the clients since
MDS now does final object unlink by itself, so drop these
max_cookiesize and default_cookiesize files.

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