CBQE-994: wait for indexers in all nodes

Change-Id: I6d65f8d344b258ab86f12a230fbc1f9ecac2259f
Reviewed-on: http://review.couchbase.org/24446
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>