Merge r1520445, r1672985, r1672989, r1673769 from trunk:

Add a warning if protocol given in SSLProtocol  or SSLProxyProtocol will override other parameters given in the same directive.
This could be a missing + or - prefix.

PR 52820

Tweak log message

Add CHANGES entry before backport proposal

Follow-up to r1520445:

Tweak error message for clarity

Submitted by: jailletc36, trawick
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1674655 13f79535-47bb-0310-9956-ffa450edef68