This is an Ubuntu delta and adds a basic HTTP/2 DEP8 test. It was submitted via Debian bug #884068 by Christian Ehrhardt, and I just grabbed his commit https://git.launchpad.net/~paelzer/apache2/commit/?h=test-for-http2&id=8f4aa68765a20d5fffa0c4fe4bef3a8898f8a9cb for this MR. If this is accepted, please credit him and not me in d/changelog.