avoid dereferencing a recently apr_pool_clear()'ed event_conn_state_t *cs
in several paths where ptrans is being recycled at the end of a request.

Same as r1638879 which was for the event MPM.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1639960 13f79535-47bb-0310-9956-ffa450edef68