Make http LayoutTests work in Debian with Apache 2.4.

This patch is migrated from https://bugs.webkit.org/show_bug.cgi?id=120352
Original patch in WebKit by Allan Sandfeld Jensen <allan.jensen@digia.com>
Reviewed in WebKit by Andreas Kling.

Debian testing (jessie) and newer use Apache 2.4.

Select httpd.conf file for debian based on version, matching Fedora behavior.
Added an apache 2.4 configuration file adapted from Fedora's,
and renamed the 2.2 file to have consistent naming.

BUG=313632

Review URL: https://codereview.chromium.org/47023017

git-svn-id: svn://svn.chromium.org/blink/trunk@161058 bbb929c8-8fbe-4397-9dbb-9b2b20218538