When i_set_failure_file() is called, make sure the handlers are reset back to defaults.
When i_set_failure_file() is called, make sure the handlers are reset back
to defaults.

--HG--
branch : HEAD

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