BUG-2689: Cast exception when serializing L3Address from groupbasedpolicy policy...

BUG-2689: Cast exception when serializing L3Address from groupbasedpolicy policy.yang

When deserializing L3AddressKey, alphabetical order of key arguments
didn't match with order of related QNames as defined in yang model.

The binding-independent world retains the ordering specified in model,
while the binding-aware world requires constructor arguments to be
alpha-sorted.

Change-Id: Icb277fed97d0984ca1a60aa7add7817db727facc
Signed-off-by: Martin Ciglan <mciglan@cisco.com>
Signed-off-by: Robert Varga <rovarga@cisco.com>