Fix multiple image_id query mappings

The loadbalancer v2 proxy has the image_id query
mapping written out twice, instead that should be
compute_flavor [1].

[1] https://docs.openstack.org/api-ref/load-balancer/v2/#list-amphora

Change-Id: I886bdc222904d6e42d8ccad254ed5ae58238d089

openstack/load_balancer/v2/amphora.py

@@ -47,7 +47,7 @@ class Amphora(resource.Resource):
         'created_at',
         'updated_at',
         'image_id',
-        'image_id',
+        'compute_flavor',
     )
 
     # Properties

openstack/tests/unit/load_balancer/test_amphora.py

@@ -97,6 +97,7 @@ class TestAmphora(base.TestCase):
                 'marker': 'marker',
                 'id': 'id',
                 'loadbalancer_id': 'loadbalancer_id',
+                'compute_flavor': 'compute_flavor',
                 'compute_id': 'compute_id',
                 'lb_network_ip': 'lb_network_ip',
                 'vrrp_ip': 'vrrp_ip',