The actual problem in the ticket would be solved by d3f31cf9239e (see
#3798).  However there is still the bug that Mutt considers a
(hdr->received != 0) to be set and usable, despite not checking the
return value of mutt_parse_date().

Change mutt_read_rfc822_header() to unset an invalid received value
back to 0.  We don't do this inside mutt_read_rfc822_line() because
that would cause the next received line to be parsed.