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/init.cpp

@@ -732,12 +732,12 @@ bool AppInit2(boost::thread_group& threadGroup)
     }
 
     // see Step 2: parameter interactions for more information about these
-    fNoListen = !GetBoolArg("-listen", true);
+    fListen = GetBoolArg("-listen", true);
     fDiscover = GetBoolArg("-discover", true);
     fNameLookup = GetBoolArg("-dns", true);
 
     bool fBound = false;
-    if (!fNoListen) {
+    if (fListen) {
         if (mapArgs.count("-bind")) {
             BOOST_FOREACH(std::string strBind, mapMultiArgs["-bind"]) {
                 CService addrBind;