scripted-diff: Replace GetDataDir(true) calls with gArgs.GetDataDirNet() calls

-BEGIN VERIFY SCRIPT-
git ls-files -- 'src' ':(exclude)src/util/system.h' ':(exclude)src/util/system.cpp' | xargs sed -i 's/GetDataDir(true)/gArgs.GetDataDirNet()/g';
-END VERIFY SCRIPT-

src/qt/optionsmodel.cpp

@@ -195,7 +195,7 @@ void OptionsModel::Reset()
     QSettings settings;
 
     // Backup old settings to chain-specific datadir for troubleshooting
-    BackupSettings(GetDataDir(true) / "guisettings.ini.bak", settings);
+    BackupSettings(gArgs.GetDataDirNet() / "guisettings.ini.bak", settings);
 
     // Save the strDataDir setting
     QString dataDir = GUIUtil::getDefaultDataDirectory();