[errors] de-specialize Transient in favor of Tags.

common/config/impl/remote/remote.go

 // Copyright 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package remote
 
 import (
         "encoding/base64"
         "fmt"
         "net/http"
         "net/url"
 
         "golang.org/x/net/context"
         "google.golang.org/api/googleapi"
 
         configApi "github.com/luci/luci-go/common/api/luci_config/config/v1"
         "github.com/luci/luci-go/common/config"
-        "github.com/luci/luci-go/common/errors"
         "github.com/luci/luci-go/common/logging"
+        "github.com/luci/luci-go/common/retry/transient"
 )
 
 // ClientFactory returns HTTP client to use (given a context).
 //
 // See 'New' for more details.
 type ClientFactory func(context.Context) (*http.Client, error)
 
 // New returns an implementation of the config service which talks to the actual
 // luci-config service using given transport.
 //
@@ skipping 256 matching lines @@
 // apiErr converts googleapi.Error to an appropriate type.
 func apiErr(e error) error {
         err, ok := e.(*googleapi.Error)
         if !ok {
                 return e
         }
         if err.Code == 404 {
                 return config.ErrNoConfig
         }
         if err.Code >= 500 {
-                return errors.WrapTransient(err)
+                return transient.Tag.Apply(err)
         }
         return err
 }