-fix transmission logic in DV API

git-svn-id: https://gnunet.org/svn/gnunet@31553 140774ce-b5e7-0310-ab8b-a85725594a96
-more logging

git-svn-id: https://gnunet.org/svn/gnunet@31554 140774ce-b5e7-0310-ab8b-a85725594a96
-consider possibility that DV message arrives after direct connection was established

git-svn-id: https://gnunet.org/svn/gnunet@31555 140774ce-b5e7-0310-ab8b-a85725594a96