[1.6.x] Fixed #22161 -- Documented send() with no recipients won't raise an exception.

  specified when the email was constructed, that connection will be used.

  Otherwise, an instance of the default backend will be instantiated and

  used. If the keyword argument ``fail_silently`` is ``True``, exceptions

  raised while sending the message will be quashed.

  raised while sending the message will be quashed. An empty list of

  recipients will not raise an exception.

* ``message()`` constructs a ``django.core.mail.SafeMIMEText`` object (a

  subclass of Python's ``email.MIMEText.MIMEText`` class) or a