Index build is stuck at 100% when create index is done after kill on memcached on ephemeral bucket

Index build is stuck at 100% and not finishing.

Steps to reproduce:

1. Create a 5 node cluster with following configuration - kv-kv-kv-index-index:n1ql
2. Create an ephemeral bucket and load data to it
3. create few indexes (primary + secondary)

   CREATE PRIMARY INDEX ON default  USING GSI

   CREATE INDEX `index_name_0` ON default(VMs) WHERE  VMs IS NOT NULL  USING GSI  WITH {'defer_build': True}

   BUILD INDEX on default(`index_name_0`) USING GSI

   CREATE INDEX `index_name_1` ON default(VMs) WHERE  VMs IS NOT NULL  USING GSI  WITH {'defer_build': True}

   BUILD INDEX on default(`index_name_1`) USING GSI

   CREATE INDEX `index_name_2` ON default(VMs) WHERE  VMs IS NOT NULL  USING GSI  WITH {'defer_build': True}

   BUILD INDEX on default(`index_name_2`) USING GSI

   CREATE INDEX `index_name_3` ON default(VMs) WHERE  VMs IS NOT NULL  USING GSI  WITH {'defer_build': True}

   BUILD INDEX on default(`index_name_3`) USING GSI

4. Kill memcached on second KV node and sleep for 60sec

 kill -9 $(ps aux | pgrep 'memcached')

5. Run create index and doc mutation in parallel

CREATE INDEX `employee48f0ecbfce7242e384fb816e8a526e52job_title` ON default(job_title) WHERE  job_title IS NOT NULL  USING GSI  WITH {'defer_build': True}

CREATE INDEX `employee48f0ecbfce7242e384fb816e8a526e52join_yr` ON default(join_yr) WHERE  join_yr > 2010 and join_yr < 2014  USING GSI  WITH {'defer_build': True}

BUILD INDEX on default(employee48f0ecbfce7242e384fb816e8a526e52job_title,employee48f0ecbfce7242e384fb816e8a526e52join_yr) USING GSI

# Index building is stuck for above 2 indexes.

http://qa.sc.couchbase.com/job/test_suite_executor/449067/consoleText - test1

I'm also able to reproduce the test on local vagrant environment

It was passing till 7.1.0-1831