Add Neutron Metering Agent support

In Havana, Neutron has now a Metering Agent which gets meters from
virtual routers.

This patchs aims to allow devstack using this new service.

Change-Id: I17ad83799d60384247b98cc8a93ac032f641c721
Signed-off-by: Emilien Macchi <emilien.macchi@enovance.com>
diff --git a/README.md b/README.md
index 99e9838..c94d8bd 100644
--- a/README.md
+++ b/README.md
@@ -139,6 +139,7 @@
     enable_service q-dhcp
     enable_service q-l3
     enable_service q-meta
+    enable_service q-metering
     enable_service neutron
     # Optional, to enable tempest configuration as part of devstack
     enable_service tempest