Do not switch to maintenance mode during Jenkins safe restart

[fredg02]

If there are issue during deployment, especially while waiting for a Jenkins instance to come online during/after a safe restart, it requires extra work to fix the routes, etc manually.
Since the benefit of "dropping the curtain" during a (in most cases) relatively short safe restart, I'd recommend that we only switch to maintenance mode on demand (e.g. if we work on a JIPP for a longer time and want to avoid interruptions).

[mbarbero]

The extra work to fix the routes etc should not be manual. I made the switch-maintenance script much more resilient, so a simple call to switch-maintenance.sh <instance> off should fix everything. Could you please double check that it works for you first?

[fredg02]

sure