all: use errgo instead of fmt.Errorf

utils/ssh/ssh.go

 // Copyright 2013 Canonical Ltd.
 // Licensed under the AGPLv3, see LICENCE file for details.
 
 // Package ssh contains utilities for dealing with SSH connections,
 // key management, and so on. All SSH-based command executions in
 // Juju should use the Command/ScpCommand functions in this package.
 //
 package ssh
 
 import (
         "bytes"
-        "errors"
         "io"
         "os/exec"
         "syscall"
 
+        "github.com/juju/errgo/errors"
+
         "launchpad.net/juju-core/cmd"
 )
 
 // Options is a client-implementation independent SSH options set.
 type Options struct {
         // ssh server port; zero means use the default (22)
         port int
         // no PTY forced by default
         allocatePTY bool
         // password authentication is disallowed by default
@@ skipping 198 matching lines @@
 func Command(host string, command []string, options *Options) *Cmd {
         logger.Debugf("using %s ssh client", chosenClient)
         return DefaultClient.Command(host, command, options)
 }
 
 // Copy is a short-cut for DefaultClient.Copy.
 func Copy(targets, extraArgs []string, options *Options) error {
         logger.Debugf("using %s ssh client", chosenClient)
         return DefaultClient.Copy(targets, extraArgs, options)
 }