amavisd-release does not work with SQL quarantine (missing quar_type = "Q")

[postmaster at wf-partner.com]

Am 2017-02-16 14:03, schrieb postmaster at wf-partner.com:
> Dominic Raferd <dominic at timedicer.co.uk> wrote
>> We use file-based quarantine. I tried this change and then
>> amavisd-release does not work, I am sorry to report; there is no error
>> message - just the mail is not released and the file remains in
>> quarantine.
> 
> Thanks for your answer.
> 
> Could you try and write the whole filename including full path when
> using amavisd-release.
> I think you should get the mail resent by amavisd-release like this.
> 
> If $fn_path is emtpy $quar_type = 'Q' is used with my change.
> 
> I don't know another way to get mails resent from SQL.

I found the underlying reason of this issue. We use the sql-based 
quarantine only for banned-files and virus, but not for spam. Therefore

$spam_quarantine_method = undefined;

In amavisd-new $quar_type defaults to 'F' if $spam_quarantine_method 
does not contain "sql:" see:

>      # choose some reasonable default (simpleminded)
>      $quar_type = c('spam_quarantine_method') =~ /^sql:/i ? 'Q' : 'F';

What do you recommend to solve this issue?

Thomas Sattler