Client: always call ensureReaderClosed

Unlike a plain `net/http/client.Do()`, requests made through client/request
use the `sendRequest` function, which parses the server response, and may
convert non-transport errors into errors (through `cli.checkResponseErr()`).

This means that we cannot assume that no reader was opened if an error is
returned.

This patch changes various locations where `ensureReaderClosed` was only
called in the non-error situation, and uses a `defer` to make sure it's
always called.

`ensureReaderClosed` itself already checks if the response's body was set,
so in situations where the error was due to a transport error, calling
`ensureReaderClosed` should be a no-op.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

client/volume_create.go

@@ -12,10 +12,10 @@ import (
 func (cli *Client) VolumeCreate(ctx context.Context, options volumetypes.VolumeCreateBody) (types.Volume, error) {
 	var volume types.Volume
 	resp, err := cli.post(ctx, "/volumes/create", nil, options, nil)
+	defer ensureReaderClosed(resp)
 	if err != nil {
 		return volume, err
 	}
 	err = json.NewDecoder(resp.body).Decode(&volume)
-	ensureReaderClosed(resp)
 	return volume, err
 }