Fix skipped test reporting in CTest (#279)
Fix skipped test reporting in CTest (#279)

This is a follow-up to c67cdf2. When the SKIP_RETURN_CODE gets set to 0,
the value is interpreted as 'false', and the test property is never
actually added.

Signed-off-by: Scott K Logan <8c724d14625be4be480086a9212b212477a303ef@cottsay.net>
ament/ament_cmake,ament/ament_cmake,ament/ament_cmake