[rackspace|compute_v2] fixing broken test

tests/rackspace/requests/compute_v2/server_tests.rb

@@ -106,11 +106,7 @@ Shindo.tests('Fog::Compute::RackspaceV2 | server_tests', ['rackspace']) do
     sleep 120 unless Fog.mocking?
     
     tests('#resize_server').succeeds do
-      if Fog.mocking?
-        resize_flavor_id = flavor_id
-      else
-        resize_flavor_id = service.flavors[1]
-      end
+      resize_flavor_id = Fog.mocking? ? flavor_id : service.flavors[1].id
       service.resize_server(server_id, resize_flavor_id)
     end
     wait_for_server_state(service, server_id, 'VERIFY_RESIZE', 'ACTIVE')