rename fNoListen to fListen and move to net

- better code readability and it belongs to net
- this is a prerequisite for a pull to add -listen to the GUI

src/util.h

@@ -100,7 +100,6 @@ extern bool fPrintToConsole;
 extern bool fPrintToDebugLog;
 extern bool fServer;
 extern std::string strMiscWarning;
-extern bool fNoListen;
 extern bool fLogTimestamps;
 extern volatile bool fReopenDebugLog;