Merge r1590437, r1592500 from trunk:

mod_proxy_fcgi: Don't segfault when failing to connect to the backend.


now understood why users haven't reported the segfault (yet) when mod_proxy_fcgi
can't connect to the application

Submitted by: trawick
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1592998 13f79535-47bb-0310-9956-ffa450edef68