LU-992 doc: remove old kernels from lustre/ChangeLog

LU-992 doc: remove old kernels from lustre/ChangeLog

Remove the old and obsolete kernels from the current list of
kernel versions that Lustre works with, since this is confusing
to list kernels that are no longer supported at all.

Update kernel patch documentation to make it clear which patches
should be applied.

Update recommended e2fsprogs version to include "or newer".

Move ldiskfs README file to top-level directory.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: Ia4859b3b2bf5a8aa9faabeb43d554130143ebbe5
Reviewed-on: http://review.whamcloud.com/8186
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Jenkins
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>