Fixed "uid_validity updated unexpectedly" errors when mbox file was being recreated and index files still existed.
Fixed "uid_validity updated unexpectedly" errors when mbox file was being
recreated and index files still existed.

--HG--
branch : HEAD

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