models: remove TiDB embedded driver support

Users should all start tidb-server process and connect to it as if
it is a MySQL server with MySQL drivers.

models/models.go

@@ -55,7 +55,6 @@ var (
 	}
 
 	EnableSQLite3 bool
-	EnableTiDB    bool
 )
 
 func init() {
@@ -146,14 +145,6 @@ func getEngine() (*xorm.Engine, error) {
 			return nil, fmt.Errorf("Fail to create directories: %v", err)
 		}
 		connStr = "file:" + DbCfg.Path + "?cache=shared&mode=rwc"
-	case "tidb":
-		if !EnableTiDB {
-			return nil, errors.New("This binary version does not build support for TiDB.")
-		}
-		if err := os.MkdirAll(path.Dir(DbCfg.Path), os.ModePerm); err != nil {
-			return nil, fmt.Errorf("Fail to create directories: %v", err)
-		}
-		connStr = "goleveldb://" + DbCfg.Path
 	default:
 		return nil, fmt.Errorf("Unknown database type: %s", DbCfg.Type)
 	}

models/models_tidb.go

@@ -1,18 +0,0 @@
-// +build tidb go1.4.2
-
-// Copyright 2015 The Gogs Authors. All rights reserved.
-// Use of this source code is governed by a MIT-style
-// license that can be found in the LICENSE file.
-
-package models
-
-import (
-	_ "github.com/go-xorm/tidb"
-	"github.com/ngaut/log"
-	_ "github.com/pingcap/tidb"
-)
-
-func init() {
-	EnableTiDB = true
-	log.SetLevelByString("error")
-}