unblock the service callback

src/main/java/com/github/shadowsocks/aidl/IShadowsocksService.aidl

@@ -7,8 +7,8 @@ interface IShadowsocksService {
   int getMode();
   int getState();
 
-  void registerCallback(IShadowsocksServiceCallback cb);
-  void unregisterCallback(IShadowsocksServiceCallback cb);
+  oneway void registerCallback(IShadowsocksServiceCallback cb);
+  oneway void unregisterCallback(IShadowsocksServiceCallback cb);
 
   oneway void start(in Config config);
   oneway void stop();

src/main/java/com/github/shadowsocks/aidl/IShadowsocksServiceCallback.aidl

@@ -1,5 +1,5 @@
 package com.github.shadowsocks.aidl;
 
 interface IShadowsocksServiceCallback {
-  void stateChanged(int state, String msg);
-}
+  oneway void stateChanged(int state, String msg);
+}

src/main/scala/com/github/shadowsocks/BaseService.scala

@@ -106,9 +106,8 @@ trait BaseService {
       override def run() {
         if (state != s) {
           val n = callbacks.beginBroadcast()
-          val m = if (msg != null) msg.substring(0, 64) else null
           for (i <- 0 to n - 1) {
-            callbacks.getBroadcastItem(i).stateChanged(s, m)
+            callbacks.getBroadcastItem(i).stateChanged(s, msg)
           }
           callbacks.finishBroadcast()
           state = s