[ci] fix travis build

Signed-off-by: Leo Chen <leo@harmony.one>

api/proto/message/message.proto

@@ -1,5 +1,6 @@
 syntax = "proto3";
 package message;
+option go_package="./;message";
 
 
 // Client is the service used for any client-facing requests.

api/service/legacysync/downloader/proto/downloader.proto

@@ -1,6 +1,7 @@
 syntax = "proto3";
 
 package downloader;
+option go_package="./;downloader";
 
 // Downloader is the service used for downloading/sycning blocks.
 service Downloader {

p2p/stream/protocols/sync/message/msg.proto

@@ -1,7 +1,7 @@
 syntax = "proto3";
 package harmony.stream.sync.message ;
 
-option go_package = "message";
+option go_package = "./;message";
 
 message Message {
   oneof req_or_resp {