-add assertion

git-svn-id: https://gnunet.org/svn/gnunet@34736 140774ce-b5e7-0310-ab8b-a85725594a96
-eliminate duplicate all_zeros globals, eliminated dead 'latency' field in SendOKMessage

git-svn-id: https://gnunet.org/svn/gnunet@34737 140774ce-b5e7-0310-ab8b-a85725594a96