The TEST_IMAGE variable went away and was replaced with the
TESTIMAGE_AUTO variable. Fixed all related/affected areas.
(From yocto-docs rev: 84e2c149fa823ab6e12be17b049c9bae1c1dd904)
Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>