*Always* send a shutdown signal to enable custom shutdown actions

NOTE: This is required to be sure that we can properly shut down the RPC
      thread.

Signed-off-by: Giel van Schijndel <me@mortis.eu>

src/bitcoinrpc.cpp

@@ -2884,8 +2884,7 @@ void ThreadRPCServer2(void* parg)
     }
 
     vnThreadsRunning[THREAD_RPCLISTENER]--;
-    while (!fShutdown)
-        io_service.run_one();
+    io_service.run();
     vnThreadsRunning[THREAD_RPCLISTENER]++;
 
     // Terminate all outstanding accept-requests