Handle more exceptions from smtplib when sending mail
Handle more exceptions from smtplib when sending mail

It's not well documented but smtplib can raise exceptions that are not SMTPException,
such as ConnectionRefusedError. So if we catch OSError instead of SMTPException
we should be able to handle these as well. Discussion at https://bugs.python.org/issue2118

RudolfCardinal/pythonlib,RudolfCardinal/pythonlib