Auto update restart runs when rebuilding user list

[CA2MI]

When you have the "auto update unattended_reboot: enabled: true" set and you are running the "./algo update-users" command, the server will restart as it's scheduled. However, it ignores if the ./algo update-users process is running. So I'm not sure what it does, but it does not run the ./algo update-users successfully. The users that I wanted to remove could still connect after the update restarted. Since I was not present for this to view, I can't see what exactly happened. But It did happen to 3 of my 12 Algo servers I run remotely.

[jackivanov]

You can change the unattended reboot time frame if it conflicts with update-users runs https://github.com/trailofbits/algo/blob/master/config.cfg#L75-L77