Add route update test cases

Author: hoffmaen

spec/unit/messages/route_update_message_spec.rb

@@ -28,6 +28,16 @@ module VCAP::CloudController
         expect(message).to be_valid
       end
 
+      it 'accepts options: nil to unset options' do
+        message = RouteUpdateMessage.new(params.merge(options: nil))
+        expect(message).to be_valid
+      end
+
+      it 'accepts lb_algo: nil to unset load-balancing algorithm' do
+        message = RouteUpdateMessage.new(params.merge(options: { lb_algo: nil }))
+        expect(message).to be_valid
+      end
+
       it 'does not accept any other params' do
         message = RouteUpdateMessage.new(params.merge(unexpected: 'unexpected_value'))
         expect(message).not_to be_valid