Set group name for wsgi/ceilometer-api process

Group name is required to get an access to api config file and
prevent permission denied error for the wsgi process.

Change-Id: I920d57a89dbf9fa570f1d4c5e987a2d6e30d9a9c
diff --git a/ceilometer/files/ocata/ceilometer.apache2.conf.Debian b/ceilometer/files/ocata/ceilometer.apache2.conf.Debian
index 988ab30..a0406fe 100644
--- a/ceilometer/files/ocata/ceilometer.apache2.conf.Debian
+++ b/ceilometer/files/ocata/ceilometer.apache2.conf.Debian
@@ -2,7 +2,7 @@
 Listen {{ server.bind.host }}:{{ server.bind.port }}
 
 <VirtualHost *:{{ server.bind.port }}>
-    WSGIDaemonProcess ceilometer-api processes=2 threads=10 user=ceilometer display-name=%{GROUP}
+    WSGIDaemonProcess ceilometer-api processes=2 threads=10 user=ceilometer group=ceilometer display-name=%{GROUP}
     WSGIProcessGroup ceilometer-api
     WSGIScriptAlias / /usr/share/ceilometer/app.wsgi
     WSGIApplicationGroup %{GLOBAL}