If the worker fails to launch, ensure the task is shown as failed rather
than a confusing "all succeeded" message.
Patch from Juro Bystricky
[YOCTO #10335]
(Bitbake rev: 0e9a2ff96d138641501874a1cd7aa6cc7e94d727)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>