Patch backport of upstream 1588 as we don't (yet) use the NetMsgType namespace

src/main.cpp

@@ -5082,7 +5082,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         }
     }
 
-    else if (strCommand == NetMsgType::NOTFOUND) {
+    else if (strCommand == "notfound") {
         // We do not care about the NOTFOUND message, but logging an Unknown Command
         // message would be undesirable as we transmit it ourselves.
     }