Remove support for cbq_bridge based index scan

Index querying system will be using queryport binary protocol
for streaming index scan results.

Change-Id: I1b3470a0a13467341ba7329918d93e72b964fd9f
Reviewed-on: http://review.couchbase.org/43030
Reviewed-by: Pratap Chakravarthy <prataprc@couchbase.com>
Tested-by: Sarath Lakshman <sarath@couchbase.com>
Reviewed-by: Sarath Lakshman <sarath@couchbase.com>