@canonical.com is now DKIM signed and SPF published which means emails
from proposed-migration running on snakefruit sending direct would
likely be caught out. Since we're here, the project is Ubuntu related
so switch to using an @ubuntu.com address instead.
It works like this. We wait until all tests have finished running. and
then grab their results. If there are any regressions, we mail each bug
with a link to pending-sru.html. There's a state file which records the
mails we've sent out, so that we don't mail the same bug multiple times.
