Fix dbPrefix not handling none when using convert command

Author: sandtechnology

src/main/java/org/maxgamer/quickshop/command/subcommand/SubCommand_Convert.java

@@ -86,7 +86,10 @@ public void onCommand(@NotNull ConsoleCommandSender sender, @NotNull String comm
             String port = dbCfg.getString("port");
             String databaseStr = dbCfg.getString("database");
             boolean useSSL = dbCfg.getBoolean("usessl");
-            String prefix = dbCfg.getString("prefix", "");
+            String prefix = dbCfg.getString("prefix");
+            if (prefix == null || "none".equals(prefix)) {
+                prefix = "";
+            }
             Map<String, String> optionsMap = new HashMap<>();
             for (String options : dbCfg.getStringList("mysql-connect-options")) {
                 String[] strings = options.split("=", 2);
@@ -95,9 +98,10 @@ public void onCommand(@NotNull ConsoleCommandSender sender, @NotNull String comm
                 }
             }
             running = true;
+            final String finalPrefix = prefix;
             plugin.getServer().getScheduler().runTaskAsynchronously(plugin, () -> {
                 try {
-                    AbstractDatabaseCore dbCore = new MySQLCore(plugin, Objects.requireNonNull(host, "MySQL host can't be null"), Objects.requireNonNull(user, "MySQL username can't be null"), Objects.requireNonNull(pass, "MySQL password can't be null"), Objects.requireNonNull(databaseStr, "MySQL database name can't be null"), Objects.requireNonNull(port, "MySQL port can't be null"), prefix, useSSL, optionsMap);
+                    AbstractDatabaseCore dbCore = new MySQLCore(plugin, Objects.requireNonNull(host, "MySQL host can't be null"), Objects.requireNonNull(user, "MySQL username can't be null"), Objects.requireNonNull(pass, "MySQL password can't be null"), Objects.requireNonNull(databaseStr, "MySQL database name can't be null"), Objects.requireNonNull(port, "MySQL port can't be null"), finalPrefix, useSSL, optionsMap);
                     DatabaseManager databaseManager = new DatabaseManager(QuickShop.getInstance(), dbCore);
                     sender.sendMessage(ChatColor.GREEN + "Converting...");
                     transferShops(new SimpleDatabaseHelper(plugin, databaseManager), sender);