This bug was fixed in the package dovecot - 1:1.2.9-1ubuntu6
---
dovecot (1:1.2.9-1ubuntu6) lucid; urgency=low
[Ante Karamatic]
* dovecot-example.conf, debian/dovecot-common.dirs,
debian/01-dovecot-postfix.auth,
debian/01-dovecot-postfix.conf, debian/control,
This leads to another effect: the dovecot deliver command may complain
like this Fatal: postmaster_address setting not given. The problem
is, that dovecot's deliver command defined in master.cf needs the -c
parameter too:
dovecot unix - n n - - pipe
flags=DRhu