LU-9897 utils: make liblnetconfig a hard requirment

LU-9897 utils: make liblnetconfig a hard requirment

With the recent changes to LNet lnetctl is now really a hard
requirment. This patch makes lustre require libyaml libraries
in order to build. In turn liblnetconfig and lnetctl are now
always built.

Test-Parameters: trivial

Change-Id: I26ff9397f3d5ba11da5ab4e76658ffd8c27ed035
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/30204
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Sonia Sharma <sonia.sharma@intel.com>
Reviewed-by: Olaf Weber <olaf.weber@hpe.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>