core: Do not load settings version

It should be used only for migration.

src/core/settings.cpp

@@ -126,8 +126,6 @@ void Settings::load()
     installId = settings->value(QStringLiteral("install_id"),
                                   // Avoid curly braces (QTBUG-885)
                                   QUuid::createUuid().toString().mid(1, 36)).toString();
-    version = settings->value(QStringLiteral("version"),
-                                QCoreApplication::applicationVersion()).toString();
     settings->endGroup();
 }
 
@@ -178,6 +176,7 @@ void Settings::save()
 
     settings->beginGroup(GroupInternal);
     settings->setValue(QStringLiteral("install_id"), installId);
+    // Version of configuration file format, should match Zeal version. Used for migration rules.
     settings->setValue(QStringLiteral("version"), QCoreApplication::applicationVersion());
     settings->endGroup();
 

src/core/settings.h

@@ -77,8 +77,6 @@ public:
     // a settings wipe. It is not attached to user hardware or software, and is sent exclusevely
     // to *.zealdocs.org hosts.
     QString installId;
-    // Version of configuration file format, should match Zeal version. Useful for migration rules.
-    QString version;
 
     ProxyType proxyType = ProxyType::System;
     QString proxyHost;