fix usage of setLinkUp/Down

tui/menu.cpp

@@ -730,8 +730,8 @@ void Menu::interfaceSelect(WINDOW *window, QString interface) {
     }else if(c == '+') {
       QString error;
 
-      if(!obj.setLinkUp(error)) {
-        QString err = QString("Could not change link state: ") + error;
+      if(obj.setLinkUp() != 0) {
+        QString err = "Could not change link state.";
         QByteArray arr = err.toLatin1();
         const char *errorString = arr.constData();
 
@@ -744,8 +744,8 @@ void Menu::interfaceSelect(WINDOW *window, QString interface) {
     }else if(c == '-') {
       QString error;
 
-      if(!obj.setLinkDown(error)) {
-        QString err = QString("Could not change link state: ") + error;
+      if(obj.setLinkDown() != 0) {
+        QString err = "Could not change link state.";
         QByteArray arr = err.toLatin1();
         const char *errorString = arr.constData();