Replace DEFAULT section with service_credentials

Some options defined in ceilometer.service should be in service_credentials
section instead of DEFAULT, which is deprecated since Havana.

Change-Id: I69077394a77f379db2be593a9fa15d414015610a
diff --git a/lib/ceilometer b/lib/ceilometer
index 5030b3c..5476773 100644
--- a/lib/ceilometer
+++ b/lib/ceilometer
@@ -155,10 +155,11 @@
     fi
 
     # the compute and central agents need these credentials in order to
-    # call out to the public nova and glance APIs
-    iniset $CEILOMETER_CONF DEFAULT os_username ceilometer
-    iniset $CEILOMETER_CONF DEFAULT os_password $SERVICE_PASSWORD
-    iniset $CEILOMETER_CONF DEFAULT os_tenant_name $SERVICE_TENANT_NAME
+    # call out to other services' public APIs
+    # the alarm evaluator needs these options to call ceilometer APIs
+    iniset $CEILOMETER_CONF service_credentials os_username ceilometer
+    iniset $CEILOMETER_CONF service_credentials os_password $SERVICE_PASSWORD
+    iniset $CEILOMETER_CONF service_credentials os_tenant_name $SERVICE_TENANT_NAME
 
     iniset $CEILOMETER_CONF keystone_authtoken auth_host $KEYSTONE_AUTH_HOST
     iniset $CEILOMETER_CONF keystone_authtoken auth_port $KEYSTONE_AUTH_PORT