user From:support@m.d.n for error emails

using 'paste@localhost' causes failures to deliver, as the sender
address is unrouteable and and relay servers will likely reject it.

Signed-off-by: Mattia Rizzolo <mattia@debian.org>
3 jobs for live in 4 minutes and 17 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Test
passed #153814
flake8

00:01:31

passed #153813
stable-bpo

00:03:48

84.0%
passed #153812
unstable

00:04:17

84.0%