ceilometer does not set db in conf file

Set [database]connection option to mongodb rather than sqlite as mongodb
is the only fully supported db.

Change-Id: I2b9fbc65de4476593d456a782dbc7e6540a75141
Fixes: bug #1186240
diff --git a/lib/ceilometer b/lib/ceilometer
index 90a1884..50060a7 100644
--- a/lib/ceilometer
+++ b/lib/ceilometer
@@ -91,6 +91,8 @@
     iniset $CEILOMETER_CONF keystone_authtoken admin_tenant_name $SERVICE_TENANT_NAME
     iniset $CEILOMETER_CONF keystone_authtoken signing_dir $CEILOMETER_AUTH_CACHE_DIR
 
+    iniset $CEILOMETER_CONF database connection mongodb://localhost:27017/ceilometer
+
     configure_mongodb
 
     cleanup_ceilometer