metering driver default value is different in code and config file

We defined the metering driver is IptablesMeteringDriver in config,
but in code, the driver is NoopMeteringDriver.

Change-Id: Ia4fb6751e8a9919f844ef27a303e2fa95b46670e
Closes-Bug: #1360958
Merge "metering driver default value is different in code and config file"