Enable Keystone under Apache by default

Make the default run mode of Keystone HTTPD + mod_wsgi. This will
enable gating on Keystone under mod_wsgi.

Depends On: https://review.openstack.org/#/c/100764/

Change-Id: I4b664a1d6c9bbb1ff999158f3a8c8ab3bd8d891b
diff --git a/README.md b/README.md
index 7185e9d..7eacebd 100644
--- a/README.md
+++ b/README.md
@@ -143,6 +143,8 @@
 Each service that can be run under HTTPD + mod_wsgi also has an override
 toggle available that can be set in your ``local.conf``.
 
+Keystone is run under HTTPD + mod_wsgi by default.
+
 Example (Keystone):
 
     KEYSTONE_USE_MOD_WSGI="True"