If the scripts/postinst-intercepts is owned by root/root then the copyfile() calls
will fail due to chown issues. We don't care about ownership of these files so
use shutil.copy() instead which won't perform any chown.
(From OE-Core rev: 1a03c70c282b3445b93a4c70ea6d40a1778750c5)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>