workaround lack of quantum/nova floatingip integration

bug 1040956

The Nova/Quantum integration in Folsom does not yet proxy Nova
floating IP calls to Quantum.  However, Horizon automatically
makes calls to Nova to list floating IPs, which prior to this
patch resulted in a Horizon error message due to the fact that
the Quantum integration code in Nova would raise an Unimplemented
error.  This patch changes that behavior to instead return an
empty list.

This is a workaround for Folsom.  The correct long-term behavior
is either to:
1) have Nova proxy all floating-ip calls to Quantum when quantum
is enabled.
2) have Horizon use the Quantum floating-ip API when Quantum
is enabled.

Change-Id: I5414d935e872a9da108511b50e70545d82b73347

nova/network/quantumv2/api.py

@@ -283,16 +283,16 @@ def get_floating_ip(self, context, id):
         raise NotImplementedError()
 
     def get_floating_ip_pools(self, context):
-        raise NotImplementedError()
+        return []
 
     def get_floating_ip_by_address(self, context, address):
         raise NotImplementedError()
 
     def get_floating_ips_by_project(self, context):
-        raise NotImplementedError()
+        return []
 
     def get_floating_ips_by_fixed_address(self, context, fixed_address):
-        raise NotImplementedError()
+        return []
 
     def get_instance_id_by_floating_address(self, context, address):
         raise NotImplementedError()