Switch over to the new pollset API.

* server/mpm/worker/worker.c:
  (listener_thread): create and add sockets to the pollset using the new
    APIs. rearrange the round-robin a little bit to work with the new
    pollset return values.
    cleaning: get rid of an extraneous status variable. get rid of
      obsoleted round-robin code.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@101801 13f79535-47bb-0310-9956-ffa450edef68