'color_characteristics_config_error' test ensures that all code paths in
parse_color_characteristics() and wet_output_set_color_characteristics()
get exercised. The return value and logged error messages are checked.
Other cases test the weston_hdr_metadata_type1 validation.
These are for the sake of test coverage, but also an example of how to
test a function from main.c, and how to capture messages from
weston_log().
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
