Remove tabs and trailing whitespaces from protocol spec.

Change-Id: I721758de8b4cecf3459e07577304a548dd397ee8
Reviewed-on: http://review.couchbase.org/42806
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: John Liang <johliang00@gmail.com>