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

common/gcloud/gs/gs.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 gs
 
 import (
         "fmt"
         "io"
         "net/http"
@@ skipping 123 matching lines @@
         // First stage: CopyTo
         err = retry.Retry(c, retry.TransientOnly(retry.Default), func() error {
                 if _, err := dstObj.CopierFrom(srcObj).Run(c); err != nil {
                         // The storage library doesn't return gs.ErrObjectNotExist when Delete
                         // returns a 404. Catch that explicitly.
                         if isNotFoundError(err) {
                                 return err
                         }
 
                         // Assume all unexpected errors are transient.
-                        return errors.WrapTransient(err)
+                        return retry.Tag.Apply(err)
                 }
                 return nil
         }, func(err error, d time.Duration) {
                 log.Fields{
                         log.ErrorKey: err,
                         "delay":      d,
                         "src":        src,
                         "dst":        dst,
                 }.Warningf(c, "Transient error copying GS file. Retrying...")
         })
@@ skipping 24 matching lines @@
         return retry.Retry(c, retry.TransientOnly(retry.Default), func() error {
                 if err := o.Delete(c); err != nil {
                         // The storage library doesn't return gs.ErrObjectNotExist when Delete
                         // returns a 404. Catch that explicitly.
                         if isNotFoundError(err) {
                                 // If the file wasn't found, then the delete "succeeded".
                                 return nil
                         }
 
                         // Assume all unexpected errors are transient.
-                        return errors.WrapTransient(err)
+                        return retry.Tag.Apply(err)
                 }
                 return nil
         }, func(err error, d time.Duration) {
                 log.Fields{
                         log.ErrorKey: err,
                         "delay":      d,
                 }.Warningf(c, "Transient error deleting file. Retrying...")
         })
 }
 
@@ skipping 31 matching lines @@
         // The storage library doesn't return gs.ErrObjectNotExist when Delete
         // returns a 404. Catch that explicitly.
         if t, ok := err.(*googleapi.Error); ok {
                 switch t.Code {
                 case http.StatusNotFound:
                         return true
                 }
         }
         return false
 }