Upr open connection packet bytes should be 32 not 28

Change-Id: Id973dc60c6c9e1c4b72bf4c3406289923f8b98e6
Reviewed-on: http://review.couchbase.org/29902
Reviewed-by: David Liao <david.liao@couchbase.com>
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>