Merge r1564756 from trunk:

mod_proxy_fcgi: Fix error message when an unexpected protocol version
number is received from the application.

PR: 56110

Submitted by: trawick
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1569007 13f79535-47bb-0310-9956-ffa450edef68