db/simple: drop redundant "virtual"

src/db/plugins/simple/SimpleDatabasePlugin.hxx

@@ -108,8 +108,8 @@ public:
 	bool Unmount(const char *uri);
 
 	/* virtual methods from class Database */
-	virtual void Open() override;
-	virtual void Close() override;
+	void Open() override;
+	void Close() override;
 
 	const LightSong *GetSong(const char *uri_utf8) const override;
 	void ReturnSong(const LightSong *song) const override;
@@ -125,7 +125,7 @@ public:
 
 	DatabaseStats GetStats(const DatabaseSelection &selection) const override;
 
-	virtual time_t GetUpdateStamp() const override {
+	time_t GetUpdateStamp() const override {
 		return mtime;
 	}