Switch luxi submit job calls to use MetaOpCode

This patch changes the luxi submit job calls to use wrapped opcodes,
and therefore it changes Hbal to submit actual meta opcodes. For
nicety, hbal also submits a comment now, showing who generated the
job.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>