[Evolution] zombie mail account won't give up trying to get data from deleted mailbox

[Dan Kortschak <dan kortschak io>]

Hello,

I have recently deleted an account, for the sake of this mail the
account is user example com, in Evolution and the associated mail box
at my email service provider.

Despite this, I continue to see errors 

```
Failed to refresh folder “user example com : INBOX”.

The reported error was “No data source found for UID
“deadbeefdeadbeefdeadbeefdeadbeefdeadbeaf””.
```

and then

```
Error while Retrieving folder list for user example com”.

No data source found for UID “deadbeefdeadbeefdeadbeefdeadbeefdeadbeaf”
```

These errors make sense, since the mail box no longer exists, but why,
given that the account was deleted from Evolution, does it keep trying?

I am unable to find a reference to the user example com account in
.config/evolution, nor can I find it in the accounts via the
preferences menu.

What is likely the cause of this and how can I stop it?

I am using Evolution 3.28.5-0ubuntu0.18.04.1 on Ubuntu 18.04.4.

thanks
Dan Kortschak