LU-2675 utils: remove loadgen

LU-2675 utils: remove loadgen

Remove lustre/utils/loadgen.c. It doesn't work and is not being
maintained.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I214cbbde5a3f18dd2050e852d33cca2bc2998b6a
Reviewed-on: http://review.whamcloud.com/12395
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Alexey Lyashkov <alexey.lyashkov@seagate.com>