breakfix: Interval not reset on config reload

[djt]

Describe the issue

@greenpau I've been using this and it works great, one little bug though that may be due to my own config.

I have the --watch flag run with caddy to update on config changes, and was recently testing out a new server config. It looks like the timer from the prior config does not end when a new one is loaded.

A quick test will allow you to see, set "update every 1" in the config and then edit it to "update every 60", config will reload but the old timer will still run. If you repeat this, even for an unrelated config change, multiple timers can be seen running.

Let me know if you need any further details.