confusing message when snapd-control is disconnected and refresh.timer=managed

[Zygmunt Krynicki]

When a device agent is managing refreshes by setting refresh.timer=managed and using snapd-control interface everything behaves correctly. When the snapd-control interface is disconnected a confusing message is logged by the refresh code:

autorefresh.go:349: cannot use refresh.timer configuration: cannot parse "managed": "managed" is not a valid weekday

[Maciej Borzecki (maciek-borzecki)]

I've proposed a fix in https://github.com/snapcore/snapd/pull/8908