Charm should only write out configs and call autocert on changes

[Haw Loeung]

Hi,

When rolling out latest charm, which should only change the shipped out cron job, the autocert charm writes out all site configs in /etc/autocert/haproxy/ (or whatever service). It then calls autocert:

| tracer: ++ queue handler reactive/autocert.py:372:configure_autocert
| 2020-06-23 02:54:50 INFO juju-log Invoking reactive handler: reactive/autocert.py:372:configure_autocert
| 2020-06-23 02:54:50 DEBUG juju-log Writing file /etc/autocert/haproxy/mysite.ini root:root 640
| ...
| 2020-06-23 02:55:00 INFO juju-log Running autocert...
| 2020-06-23 02:55:13 DEBUG config-changed OK: Service 'haproxy', cert 'mysite' is present and correct
| ...
| 2020-06-23 02:55:13 INFO juju-log Successfully ran autocert

This also happens on config-changed enabling 'run_weekdays'. I think it should only write out configs on disk if the contents have changed and also call autocert (which then triggers service reload) on config changes.