busybox's unzip test case requires zip command. However, busybox
itself does not provide one. So add zip as a runtime dependency.
(From OE-Core rev: 223e5c3e1f7cb4001961347c85505d88a52d221f)
Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>