distinguish between these two states:

. just issued connect(), polling for writability to find out when connect()
  completed
. already connected, waiting for data from the server so polling for
  readability

by only polling for writability during the first state, we avoid some
logic in test() which inappropriately writes multiple requests to the
server

btw, the most basic SSL test segfaulted before and after this commit


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@100889 13f79535-47bb-0310-9956-ffa450edef68