Add a toy manifest for building secondary index components

Change-Id: I7144251741c194b841f668bfe25ba8509bbf936c
Reviewed-on: http://review.couchbase.org/41577
Reviewed-by: Sarath Lakshman <sarath@couchbase.com>
Tested-by: Sarath Lakshman <sarath@couchbase.com>