Unbreak command line job submission

A change introduced in 5299e61f modified the contents of
JobExecutor.jobs, missing a place where this tuple was deconstructed.
This creates a traceback in gnt-* <any> --submit, fixed by this patch.

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