LU-3466 iokit: Make lustre-iokit a subpackage of lustre

LU-3466 iokit: Make lustre-iokit a subpackage of lustre

Remove build_iokit from lbuild
Remove lustre-iokit.spec.in and merge with lustre.spec.in
Use of --disable-iokit and remove support for building external
Remove iokit script from main lustre package.
Add lustre-iokit dependency to lustre-tests rpm
Disable building iokit rpm for client build

Signed-off-by: Minh Diep <minh.diep@intel.com>
Change-Id: I34889b97b5bdbb201ee88d71e1668f419e640cdb
Reviewed-on: http://review.whamcloud.com/7314
Reviewed-by: Brian J. Murrell <brian.murrell@intel.com>
Tested-by: Hudson
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Christopher J. Morrone <chris.morrone.llnl@gmail.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>