Merge r1679428, r1679432 from trunk:

Conform to RFC 7525, with additional suggestion to drop RSA Kx ciphers

Document RFC 7525 changes
Submitted by: wrowe
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1679987 13f79535-47bb-0310-9956-ffa450edef68