Merge r1729208, r1735668, r1735668, r1735931, r1735935, r1735942 from trunk:

let proxy handler forward ALPN protocol strings for ssl proxy connections

Remove leftover comment

Remove leftover comment

APLOGNO update for mod_proxy_http2

fix APLOGNO at wrong place, me stupid

h2_proxy_session: fill in missing APLOGNO()s.
Submitted by: icing, jailletc36, jailletc36, icing, icing, ylavic
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1743577 13f79535-47bb-0310-9956-ffa450edef68