LU-11514 lnet: separate ni state from recovery

LU-11514 lnet: separate ni state from recovery

To make the code more readable we make the ni_state an
enumerated type, and create a separate bit filed to track
the recovery state. Both of these are protected by the
lnet_ni_lock()

Signed-off-by: Amir Shehata <ashehata@whamcloud.com>
Change-Id: I5acfccecffd5dbb07c9ad3b1c7651cf291b85cb8
Reviewed-on: https://review.whamcloud.com/33361
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Sonia Sharma <sharmaso@whamcloud.com>
Reviewed-by: Doug Oucharek <dougso@me.com>
Reviewed-by: Olaf Weber <olaf.weber@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>