if start fails, clean up and exit


git-svn-id: https://gnunet.org/svn/gnunet@31472 140774ce-b5e7-0310-ab8b-a85725594a96
- log fixes, limit kx to live tunnels


git-svn-id: https://gnunet.org/svn/gnunet@31473 140774ce-b5e7-0310-ab8b-a85725594a96