- Keepalives should NOT be transmitted in the clear

git-svn-id: https://gnunet.org/svn/gnunet@34008 140774ce-b5e7-0310-ab8b-a85725594a96
- only an error if counter was wrong

git-svn-id: https://gnunet.org/svn/gnunet@34009 140774ce-b5e7-0310-ab8b-a85725594a96
- make sure connection is destroyed and no use-after-free happens

git-svn-id: https://gnunet.org/svn/gnunet@34010 140774ce-b5e7-0310-ab8b-a85725594a96