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.

LTD-Beget/dovecot,Distrotech/dovecot,Distrotech/dovecot,LTD-Beget/dovecot,damoxc/dovecot,damoxc/dovecot,Distrotech/dovecot,Distrotech/dovecot,LTD-Beget/dovecot,damoxc/dovecot,LTD-Beget/dovecot,LTD-Beget/dovecot,damoxc/dovecot,Distrotech/dovecot,damoxc/dovecot