[vpython] Verify environment, named installs.

vpython/application/subcommand_delete.go

 // Copyright 2017 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 application
 
 import (
         "github.com/maruel/subcommands"
         "golang.org/x/net/context"
 
         "github.com/luci/luci-go/vpython/venv"
 
         "github.com/luci/luci-go/common/cli"
         "github.com/luci/luci-go/common/errors"
         "github.com/luci/luci-go/common/logging"
 )
 
 var subcommandDelete = &subcommands.Command{
         UsageLine: "delete",
         ShortDesc: "deletes existing VirtualEnv",
         LongDesc:  "offers deletion options for existing vpython VirtualEnv installatioins",
         Advanced:  false,
         CommandRun: func() subcommands.CommandRun {
                 var cr deleteCommandRun
 
                 fs := cr.GetFlags()
-                fs.BoolVar(&cr.all, "all", false, "Delete all VirtualEnv environments, rather than the current ones.")
+                fs.BoolVar(&cr.all, "all", cr.all, "Delete all VirtualEnv environments, rather than the current ones.")
 
                 return &cr
         },
 }
 
 type deleteCommandRun struct {
         subcommands.CommandRunBase
 
         all bool
 }
@@ skipping 32 matching lines @@
                 }
 
                 if failures > 0 {
                         return errors.Reason("failed to delete %(count)d environment(s)").
                                 D("count", failures).
                                 Err()
                 }
                 return nil
         })
 }