The previous attempt at soft-failing when uninative was enabled didn't actually
work, because the workers didn't evaluate the function that actually enabled
uninative.
In a BuildStarted handler we can check if we need to download or extract the
uninative tarball.
In a ConfigParsed handler on the workers we can check if the uninative loader is
present, and if so enable it.
Signed-off-by: Ross Burton <ross.burton@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
