Consider the resources from failed operations as overloaded and not use them
until the parallelism is refreshed.

This commit also fixes a bug where the parallelism is set to 0 and hence no
progress can be made.


git-svn-id: https://gnunet.org/svn/gnunet@32387 140774ce-b5e7-0310-ab8b-a85725594a96
Do not let parallelism fall below the default parallelism value for adaptive queues.


git-svn-id: https://gnunet.org/svn/gnunet@32388 140774ce-b5e7-0310-ab8b-a85725594a96