maildir_storage_sync_force() crashed if called from mail index sync/expunge callbacks.
maildir_storage_sync_force() crashed if called from mail index sync/expunge
callbacks.

--HG--
branch : HEAD

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