Merge branch 'master' of git+ssh://db.debian.org/git/dsa-nagios

Merge branch 'master' of git+ssh://db.debian.org/git/dsa-nagios

* 'master' of git+ssh://db.debian.org/git/dsa-nagios: (48 commits)
  upgraded diabelli from jessie to stretch
  porta on stretch
  loghost-grnet-01 on stretch
  lotti on stretch
  mirror-conova on stretch
  muffat on stretch
  lully on stretch
  prokofiev on stretch
  decomission franck rt#6464
  decomission franck rt#6464
  draghi is now on stretch
  decomission franck rt#6464
  aagaard on stretch
  pieta on stretch
  petterson: add note about no need to upgrade to Stretch
  decomission praetorius rt#6714
  mirror-accumu on stretch
  Decommission porpora.debian.org
  lobos on stretch
  mirror-anu on stretch
  ...