environs: add UploadTools method

environs/dummy/environs.go

 package dummy
 
 import (
         "bytes"
         "errors"
         "fmt"
         "io"
         "io/ioutil"
         "launchpad.net/juju/go/environs"
         "launchpad.net/juju/go/schema"
@@ skipping 244 matching lines @@
         if err != nil {
                 return err
         }
         e.state.mu.Lock()
         e.state.files[name] = buf.Bytes()
         e.state.mu.Unlock()
         return nil
 }
 
 func (*environ) UploadTools(r io.Reader, length int64, version version.Version) error {
-        return fmt.Errorf("dummy environ does not support executable upload")
+        return fmt.Errorf("dummy environment does not support executable upload")
 }
 
 func (e *environ) GetFile(name string) (io.ReadCloser, error) {
         if e.broken {
                 return nil, errBroken
         }
         e.state.mu.Lock()
         defer e.state.mu.Unlock()
         data, ok := e.state.files[name]
         if !ok {
@@ skipping 20 matching lines @@
         return m.id
 }
 
 func (m *instance) DNSName() (string, error) {
         return m.id + ".dns", nil
 }
 
 func (m *instance) WaitDNSName() (string, error) {
         return m.DNSName()
 }