I am also suffering from the inability to restart dovecot (or stop it) using "sudo service dovecot restart" but unlike the original poster I do not have dovecot-postfix installed only dovecot-common and dovecot-imap.
I am also suffering from the inability to restart dovecot (or stop it) using "sudo service dovecot restart" but unlike the original poster I do not have dovecot-postfix installed only dovecot-common and dovecot-imap.