LU-8293 lnet: Add insserv header to lnet init script

LU-8293 lnet: Add insserv header to lnet init script

The lnet init script does not contain header information as described
by the insserv man page. This header information is needed to ensure
the lnet init script is not run until openibd has been able to start

Signed-off-by: Chris Horn <hornc@cray.com>
Change-Id: I6f778e827f88ce34199dff70be5d5089f0ba51b9
Reviewed-on: https://review.whamcloud.com/20835
Tested-by: Jenkins
Reviewed-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>