Keith reported that command submission and command completion
tracepoints have the order of the cmdid and qid fields swapped.

While it isn't easily possible to change the command submission
tracepoint, as there is a regression test parsing it in blktests we
can swap the command completion tracepoint to have the fields aligned.
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reported-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Keith Busch <keith.busch@intel.com>