Fix the transport name used to start the grpc java docker server

tools/dockerfile/grpc_java/Dockerfile

@@ -13,4 +13,4 @@ RUN cd /var/local/git/grpc-java && \
   mvn install
 
 # Specify the default command such that the interop server runs on its known testing port
-CMD ["/var/local/git/grpc-java/run-test-server.sh", "--transport=NETTY_TLS", "--grpc_version=2", "--port=8030"]
+CMD ["/var/local/git/grpc-java/run-test-server.sh", "--transport=HTTP2_NETTY_TLS", "--grpc_version=2", "--port=8030"]