* Do better checking of pollset operations in various places to avoid segfaults.

PR: 46467
Submitted by: Stefan Fritsch <sf sfritsch.de>
Reviewed by: rpluem


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@804764 13f79535-47bb-0310-9956-ffa450edef68