Set display name in apache processes

This change makes apache set process group name in the process name,
so when listing the processes the user can easily identify what's
running in each apache process. This is specially useful to debug
memory consumption or when a process consumming too much CPU.

Change-Id: I9787980052f451f452d3b8e5e51385ad5aa01e6a
diff --git a/files/apache-horizon.template b/files/apache-horizon.template
index af880c4..c1dd693 100644
--- a/files/apache-horizon.template
+++ b/files/apache-horizon.template
@@ -1,6 +1,6 @@
 <VirtualHost *:80>
     WSGIScriptAlias / %HORIZON_DIR%/openstack_dashboard/wsgi/django.wsgi
-    WSGIDaemonProcess horizon user=%USER% group=%GROUP% processes=3 threads=10 home=%HORIZON_DIR%
+    WSGIDaemonProcess horizon user=%USER% group=%GROUP% processes=3 threads=10 home=%HORIZON_DIR% display-name=%{GROUP}
     WSGIApplicationGroup %{GLOBAL}
 
     SetEnv APACHE_RUN_USER %USER%