[Dovecot] Sieve tempoary script folder

[Markus Fritz]

Hello,

I got the issue that sieve wants to write his tmp files to 
/etc/dovecot/. But I want sieve to write in a folder which it has write 
rights.
I created a script to to put spam in the 'Spam' folder, put it in 
/etc/dovecot/.dovecot.sieve. When recieving a mail sieve want's to 
create a tmp file like /etc/dovecot/.dovecot.sieve.12033
How to change the desired tmp folder by sieve?