nativesdk-intercept: Fix bad intercept chgrp/chown logic

nativesdk-intercept: Fix bad intercept chgrp/chown logic

Running either of these ends up corrupting the os.execv args.

If we run:
./scripts/nativesdk-intercept/chown -R foo:foo bar

The loop here ends up missing the conversion of foo:foo to root:root because
it sees sys.argv[0] and assumes that it's the user:group argument and that we
should convert that. We end up a os.execv(path, args) that have the following
args:

['root:root', '-R', 'foo:foo', 'bar']

As os.execv ignores args[0], we can just populate it with sys.argv[0] and then
loop through sys.argv[1:]. As both chgrp and chown would have either flags and
USER[:GROUP] next, this fixes the issue.

Signed-off-by: Eilís 'pidge' Ní Fhlannagáin <pidge@baylibre.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 2a75f647ec7696d353f4b09099d777ba53f34d36)
Signed-off-by: Steve Sakoman <steve@sakoman.com>