client/server: pass back packed thread_options in add_job()

client/server: pass back packed thread_options in add_job()

Now the client can see the parsed options. As it turns out,
we need to parse locally since the client and server can be
vastly different operating systems and architectures. Pass
back the options, allowing the client to change them before
starting the job.

Signed-off-by: Jens Axboe <axboe@kernel.dk>