files.o.o : publish .log as text/plain

This is a follow on to I67870f6d439af2d2a63a5048ef52cecff3e75275 to do
the same for files.openstack.org (as
http://files.openstack.org/mirror/logs/ is a handy central place to
point people at)

Change-Id: I07c707d45ab3e3c6f87460b3346efd7026467c56

modules/openstack_project/templates/files.vhost.erb

@@ -33,4 +33,6 @@ NameVirtualHost <%= @vhost_name %>:<%= @port %>
     LogLevel warn
     CustomLog /var/log/<%= scope.lookupvar("httpd::params::apache_name") %>/<%= @name %>_access.log combined
     ServerSignature Off
+
+    AddType text/plain .log .log.1
 </VirtualHost>