Stream request response is 4 bytes not 6

Change-Id: I61080db5bdf215b5db4abd1a6dc97cf9f5b42482
Reviewed-on: http://review.couchbase.org/30266
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>