Steve Langasek 132ffaf465 Refine the logic for recording the nominal sent age of the mail
In the previous iteration, if we were ever down/frozen/disabled long enough
to miss sending two mails in a row, we would see unintended "catch-up"
behavior where each subsequent run of britney would send a mail until the
right total number of mails had been sent.  Don't do this; instead, catch us
up in one go to the most recent mail that should have been sent, avoiding
bunching of notifications.

This changes one of the tests also to match.
2017-07-06 21:14:19 -07:00
..
2016-12-12 11:33:45 +01:00
2016-12-12 11:33:45 +01:00