Configure Keystone log format

Change-Id: Ib9bcc8d00b9cd0e752fd5942efda8d677924af46
diff --git a/keystone/server/wsgi.yml b/keystone/server/wsgi.yml
index 2c8a19d..1a949e9 100644
--- a/keystone/server/wsgi.yml
+++ b/keystone/server/wsgi.yml
@@ -15,5 +15,10 @@
           name: wsgi
           host:
             name: ${linux:network:fqdn}
+          log:
+            custom:
+              format: >-
+                %v:%p %h %l %u %t \"%r\" %>s %D %O \"%{Referer}i\" \"%{User-Agent}i\"
+
       modules:
         - wsgi