Revert "[Qt] Add dbcache migration path"

This reverts commit 921b8483da.

src/qt/optionsmodel.cpp

@@ -44,8 +44,6 @@ void OptionsModel::Init(bool resetSettings)
     if (resetSettings)
         Reset();
 
-    checkAndMigrate();
-
     QSettings settings;
 
     // Ensure restart flag is unset on client startup
@@ -445,22 +443,3 @@ bool OptionsModel::isRestartRequired()
     QSettings settings;
     return settings.value("fRestartRequired", false).toBool();
 }
-
-void OptionsModel::checkAndMigrate()
-{
-    // Migration of default values
-    // Check if the QSettings container was already loaded with this client version
-    QSettings settings;
-    static const char strSettingsVersionKey[] = "nSettingsVersion";
-    int settingsVersion = settings.contains(strSettingsVersionKey) ? settings.value(strSettingsVersionKey).toInt() : 0;
-    if (settingsVersion < CLIENT_VERSION)
-    {
-        // -dbcache was bumped from 100 to 300 in 0.13
-        // see https://github.com/bitcoin/bitcoin/pull/8273
-        // force people to upgrade to the new value if they are using 100MB
-        if (settingsVersion < 130000 && settings.contains("nDatabaseCache") && settings.value("nDatabaseCache").toLongLong() == 100)
-            settings.setValue("nDatabaseCache", (qint64)nDefaultDbCache);
-
-        settings.setValue(strSettingsVersionKey, CLIENT_VERSION);
-    }
-}

src/qt/optionsmodel.h

@@ -84,11 +84,9 @@ private:
     /* settings that were overriden by command-line */
     QString strOverriddenByCommandLine;
 
-    // Add option to list of GUI options overridden through command line/config file
+    /// Add option to list of GUI options overridden through command line/config file
     void addOverriddenOption(const std::string &option);
 
-    // Check settings version and upgrade default values if required
-    void checkAndMigrate();
 Q_SIGNALS:
     void displayUnitChanged(int unit);
     void coinControlFeaturesChanged(bool);