Backport 1.60 and 1.62:

Backport 1.60 and 1.62:

Patch #586999: Fix multiline string in sendmail example.

smptlib did not handle empty addresses.
The problem was that it expected rfc822.parseaddr() to return None
upon a parse failure.  The actual, documented return value for a
parse failure is (None, None).
Closes SF bug 602029.