Fix incorrect initial migration

Also adds variant to settings

osu.Game/Rulesets/UI/RulesetContainer.cs

@@ -38,6 +38,11 @@ namespace osu.Game.Rulesets.UI
         /// </summary>
         public bool AspectAdjust = true;
 
+        /// <summary>
+        /// The selected variant.
+        /// </summary>
+        public virtual int Variant => 0;
+
         /// <summary>
         /// The input manager for this RulesetContainer.
         /// </summary>