Handling missing next hop in verify successor


git-svn-id: https://gnunet.org/svn/gnunet@34196 140774ce-b5e7-0310-ab8b-a85725594a96
debug prints


git-svn-id: https://gnunet.org/svn/gnunet@34197 140774ce-b5e7-0310-ab8b-a85725594a96