Clear c.id on Close to avoid closing twice

Signed-off-by: Kimmo Lehto <klehto@mirantis.com>

Author: kke

command.go

@@ -37,7 +37,6 @@ type Command struct {
 
 	done   chan struct{}
 	cancel chan struct{}
-	once   sync.Once
 }
 
 func newCommand(ctx context.Context, shell *Shell, ids string) *Command {
@@ -114,24 +113,19 @@ func (c *Command) check() error {
 
 // Close will terminate the running command
 func (c *Command) Close() error {
-	var err error
-
-	if err = c.check(); err != nil {
+	if err := c.check(); err != nil {
 		return err
 	}
 
-	if _, ok := <-c.cancel; !ok {
-		return nil // channel already closed, do not send a signal
-	}
+	close(c.cancel)
 
-	c.once.Do(func() {
-		close(c.cancel)
+	id := c.id
+	c.id = ""
 
-		request := NewSignalRequest(c.client.url, c.shell.id, c.id, &c.client.Parameters)
-		defer request.Free()
+	request := NewSignalRequest(c.client.url, c.shell.id, id, &c.client.Parameters)
+	defer request.Free()
 
-		_, err = c.client.sendRequest(request)
-	})
+	_, err := c.client.sendRequest(request)
 
 	return err
 }