Attempts to fix the build broke when we enabled Apache Dubbo

[codefromthecrypt]

Master has been red since we hooked it up. This change is taking guesses.

org.apache.dubbo.rpc.RpcException: Failed to invoke remote proxy method sayHello to dubbo://172.17.0.1:39321/brave.dubbo.GreeterService?anyhost=false&application=brave&bind.ip=172.17.0.1&bind.port=39321&deprecated=false&dubbo=2.0.2&dynamic=true&generic=true&interface=brave.dubbo.GreeterService&methods=*&pid=16650&register=true&release=2.7.3&side=provider&timestamp=1569838843975, cause: Not found method "sayHello" in class org.apache.dubbo.rpc.service.GenericService.

org.apache.dubbo.rpc.RpcException: Failed to invoke remote proxy method sayHello to dubbo://172.17.0.1:39321/brave.dubbo.GreeterService?anyhost=false&application=brave&bind.ip=172.17.0.1&bind.port=39321&deprecated=false&dubbo=2.0.2&dynamic=true&generic=true&interface=brave.dubbo.GreeterService&methods=*&pid=16650&register=true&release=2.7.3&side=provider&timestamp=1569838843975, cause: Not found method "sayHello" in class org.apache.dubbo.rpc.service.GenericService.

	at org.apache.dubbo.rpc.proxy.AbstractProxyInvoker.invoke(AbstractProxyInvoker.java:107)

	at org.apache.dubbo.config.invoker.DelegateProviderMetaDataInvoker.invoke(DelegateProviderMetaDataInvoker.java:56)

	at org.apache.dubbo.rpc.filter.ExceptionFilter.invoke(ExceptionFilter.java:55)

	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:82)

	at org.apache.dubbo.monitor.support.MonitorFilter.invoke(MonitorFilter.java:92)

	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:82)

	at org.apache.dubbo.rpc.filter.TimeoutFilter.invoke(TimeoutFilter.java:48)

	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:82)

	at org.apache.dubbo.rpc.protocol.dubbo.filter.TraceFilter.invoke(TraceFilter.java:81)

	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:82)

	at org.apache.dubbo.rpc.filter.ContextFilter.invoke(ContextFilter.java:96)

	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:82)

	at org.apache.dubbo.rpc.filter.GenericFilter.invoke(GenericFilter.java:148)

	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:82)

	at org.apache.dubbo.rpc.filter.ClassLoaderFilter.invoke(ClassLoaderFilter.java:38)

	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:82)

	at org.apache.dubbo.rpc.filter.EchoFilter.invoke(EchoFilter.java:41)

	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper$1.invoke(ProtocolFilterWrapper.java:82)

	at org.apache.dubbo.rpc.protocol.ProtocolFilterWrapper$CallbackRegistrationInvoker.invoke(ProtocolFilterWrapper.java:157)

	at org.apache.dubbo.rpc.protocol.dubbo.DubboProtocol$1.reply(DubboProtocol.java:152)

	at org.apache.dubbo.remoting.exchange.support.header.HeaderExchangeHandler.handleRequest(HeaderExchangeHandler.java:102)

	at org.apache.dubbo.remoting.exchange.support.header.HeaderExchangeHandler.received(HeaderExchangeHandler.java:193)

	at org.apache.dubbo.remoting.transport.DecodeHandler.received(DecodeHandler.java:51)

	at org.apache.dubbo.remoting.transport.dispatcher.ChannelEventRunnable.run(ChannelEventRunnable.java:57)

	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)

	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)

	at java.base/java.lang.Thread.run(Thread.java:834)

Caused by: org.apache.dubbo.common.bytecode.NoSuchMethodException: Not found method "sayHello" in class org.apache.dubbo.rpc.service.GenericService.

	at org.apache.dubbo.common.bytecode.Wrapper0.invokeMethod(Wrapper0.java)

	at org.apache.dubbo.rpc.proxy.javassist.JavassistProxyFactory$1.doInvoke(JavassistProxyFactory.java:47)

	at org.apache.dubbo.rpc.proxy.AbstractProxyInvoker.invoke(AbstractProxyInvoker.java:84)

	... 26 more

cc @icom2014