net: set message deserialization version when it's actually time to deserialize

We'll soon no longer have access to vRecvMsg, and this is more intuitive anyway.

src/net.h

@@ -607,7 +607,7 @@ public:
     std::list<CNetMessage> vRecvMsg;
     CCriticalSection cs_vRecvMsg;
     uint64_t nRecvBytes;
-    int nRecvVersion;
+    std::atomic<int> nRecvVersion;
 
     int64_t nLastSend;
     int64_t nLastRecv;
@@ -747,12 +747,13 @@ public:
     // requires LOCK(cs_vRecvMsg)
     bool ReceiveMsgBytes(const char *pch, unsigned int nBytes, bool& complete);
 
-    // requires LOCK(cs_vRecvMsg)
     void SetRecvVersion(int nVersionIn)
     {
         nRecvVersion = nVersionIn;
-        BOOST_FOREACH(CNetMessage &msg, vRecvMsg)
-            msg.SetVersion(nVersionIn);
+    }
+    int GetRecvVersion()
+    {
+        return nRecvVersion;
     }
     void SetSendVersion(int nVersionIn)
     {