apache-httpd: Avoid NameVirtualHost in >= v2.4.

NameVirtualHost no longer has any effect on version 2.4 and just emits ugly
warnings, so let's not use it if we use 2.4.

More information: http://httpd.apache.org/docs/2.4/upgrading.html#misc



Signed-off-by: aszlig <aszlig@redmoonstudios.org>