Similar to how this is done in the diag.sh found in the base-files
package, we should blink our status LED (if we have one) during the
upgrade process. This follows the same blink pattern as seen at
./package/base-files/files/etc/diag.sh#L36
Signed-off-by: Chris Blake <chrisrblake93@gmail.com>
(cherry picked from commit 82bec3364d)
