net/wget: set filesize

After downloading a file with wget the file size may be needed in follow up
actions, e.g.

* write file to device
* calculate hash

Let wget set the environment variable filesize.

Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
1 file changed