Owner parameter wasn't set correctly. Take user's groups from acl_groups environment.
Owner parameter wasn't set correctly. Take user's groups from acl_groups
environment.

--HG--
branch : HEAD

jwm/dovecot-notmuch,jkerihuel/dovecot,jwm/dovecot-notmuch,jkerihuel/dovecot,jkerihuel/dovecot,jwm/dovecot-notmuch,jkerihuel/dovecot,jwm/dovecot-notmuch,jkerihuel/dovecot,jwm/dovecot-notmuch