Restore custom proxyIPAddress after upgrading the CSN

If you've modified the proxyIPAddress in /var/opt/caringo/netboot/content/cluster.cfg to a value other than the default proxyIPAddress = <2nd public IP of the CSN>, you will have to take into account that this custom value might get restored back to its original default value during a CSN upgrade.

To workaround this, before upgrading the CSN you will have to keep a backup of the current value of proxyIPAddress. After the upgrade check /var/opt/caringo/netboot/content/cluster.cfg and if you see that proxyIPAddress has been restored to the default, then replace it with whatever value you had before performing the upgrade.