LU-1199 build: Refactor ldiskfs's build system

LU-1199 build: Refactor ldiskfs's build system

Lustre has a complicated build system that combines automake
files and the kernel's Makefile.in build system in a rather
serpentine system that has long chains of makefile includes,
making it very difficult for the reader to ever know exactly
which targets and reles will either be required or  available
under any specific set of conditions.

The good news is that none of that is required by ldiskfs
because ldiskfs is only built for kernel-space Linux.
We only need one fairly straight forward build path.

To simplify the build system, we:

- Remove Rules.in
- Remove all autoMakefile.am files
- Remove confusing build/Makefile
- Combine the three .m4 files into one, since
  that was just a hold-over from Lustre's build system.
- Cleanup and improve some of the m4 macros
- Remove the multi-level build/ subdirectory tree
  and replace with single-level config subdirectory.
- Fix the ldiskfs debuginfo package (actually contains
  the patched source of ldiskfs!)
- Simplify autogen.sh
- Update .gitignore files

Change-Id: I9e6112c150c1e0f9076d5e689b69534eab7a964b
Signed-off-by: Christopher J. Morrone <morrone2@llnl.gov>
Reviewed-on: http://review.whamcloud.com/4728
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Brian J. Murrell <brian.murrell@intel.com>
Reviewed-by: Minh Diep <minh.diep@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>