queryport: Add index information in protocol requests

Added index name and bucket information in stats and scan
protocol request messages.

Change-Id: I4d2cbe209e86af2164c6356b4b2ffc25c0bf190c
Reviewed-on: http://review.couchbase.org/42610
Reviewed-by: Sarath Lakshman <sarath@couchbase.com>
Tested-by: Sarath Lakshman <sarath@couchbase.com>