LU-12929 lnet: Remove field net_state in struct lnet_net

LU-12929 lnet: Remove field net_state in struct lnet_net

lnet_net.net_state is set but never used.  So the code that sets
it isn't tested and might be wrong.  Best to just remove it.

Test-Parameters: trivial
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: Ia11b8c0da0286f82c43be353944e036b5ea936c6
Reviewed-on: https://review.whamcloud.com/36655
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Chris Horn <hornc@cray.com>
Reviewed-by: Amir Shehata <ashehata@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>