ingnore the NotExist error when removing inexistent files

Signed-off-by: Shijiang Wei <mountkin@gmail.com>

daemon/graphdriver/btrfs/btrfs.go

@@ -278,7 +278,10 @@ func (d *Driver) Remove(id string) error {
 	if err := subvolDelete(d.subvolumesDir(), id); err != nil {
 		return err
 	}
-	return os.RemoveAll(dir)
+	if err := os.RemoveAll(dir); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	return nil
 }
 
 // Get the requested filesystem id.

daemon/graphdriver/overlay/overlay.go

@@ -322,7 +322,10 @@ func (d *Driver) dir(id string) string {
 
 // Remove cleans the directories that are created for this id.
 func (d *Driver) Remove(id string) error {
-	return os.RemoveAll(d.dir(id))
+	if err := os.RemoveAll(d.dir(id)); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	return nil
 }
 
 // Get creates and mounts the required file system for the given id and returns the mount path.

daemon/graphdriver/vfs/driver.go

@@ -104,10 +104,10 @@ func (d *Driver) dir(id string) string {
 
 // Remove deletes the content from the directory for a given id.
 func (d *Driver) Remove(id string) error {
-	if _, err := os.Stat(d.dir(id)); err != nil {
+	if err := os.RemoveAll(d.dir(id)); err != nil && !os.IsNotExist(err) {
 		return err
 	}
-	return os.RemoveAll(d.dir(id))
+	return nil
 }
 
 // Get returns the directory for the given id.