Handle case where email's internal time is erroneously so large as to
cause overflow errors when setting file modification time with
utime_from_header = true.
Reported-by: Cameron Simpson <cs@zip.com.au>
Signed-off-by: Janna Martl <janna.martl109@gmail.com>
Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>