*) mod_http2/mod_proxy_http2: proxy_http2 checks correct master connection aborted status

     to trigger immediate shutdown of backend connections. This is now always signalled
     by mod_http2 when the the session is being released. 
     proxy_http2 now only sends a PING frame to the backend when there is not already one
     in flight. [Stefan Eissing]

  *) mod_proxy_http2: fixed an issue where a proxy_http2 handler entered an infinite 
     loop when encountering certain errors on the backend connection. 
     See <https://bz.apache.org/bugzilla/show_bug.cgi?id=63170>. [Stefan Eissing]



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1854365 13f79535-47bb-0310-9956-ffa450edef68