MB-100: add timeout for index waiting

Change-Id: Ic142df689fb51e81ad43978fee47e69c7046ae31
Reviewed-on: http://review.couchbase.org/25015
Reviewed-by: Iryna Mironava <irynamironava@yandex.ru>
Tested-by: Iryna Mironava <irynamironava@yandex.ru>