CBQE-968: add index wait for consistency case

Change-Id: I6383f4b18599ff450e2f93a5b22ba1c64ca7aab5
Reviewed-on: http://review.couchbase.org/24045
Reviewed-by: Deepkaran Salooja <deepkaran.salooja@globallogic.com>
Tested-by: Iryna Mironava <irynamironava@yandex.ru>