Avoid returning many "inv" orphans

src/main.cpp

@@ -3639,6 +3639,11 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
 
             // Track requests for our stuff
             g_signals.Inventory(inv.hash);
+
+            if (pfrom->nSendSize > (SendBufferSize() * 2)) {
+                Misbehaving(pfrom->GetId(), 50);
+                return error("send buffer size() = %u", pfrom->nSendSize);
+            }
         }
     }