[FTS] crash on alias type query - cbft/pindex_bleve.go:370

FTS crash in this scenario .

CB version 1733 , it was observed old versions too

[Test runner result]

./testrunner -i INI_FILE.ini get-cbcollect-info=False,get-logs=False,stop-on-failure=False,compare_es=True,cluster=D+F,GROUP=P0 -t fts.stable_topology_fts.StableTopFTS.test_query_type_on_alias,dataset=wiki,items=30000,num_queries=100,query_types=match,cluster=D:F,compare_es=True,GROUP=P0

./testrunner -i INI_FILE.ini get-cbcollect-info=False,get-logs=False,stop-on-failure=False,compare_es=True,cluster=D+F,GROUP=P0 -t fts.stable_topology_fts.StableTopFTS.test_query_type_on_alias,items=30000,num_queries=100,dataset=wiki,query_types=numeric_range,cluster=D,F,F,compare_es=True,GROUP=P0

Crash Log:

https://s3.amazonaws.com/cb-customers/cbft/99/collectinfo-2016-03-09T023946-ns_1%40127.0.0.1.zip

-------------------------------------
Service 'fts' exited with status 1. Restarting. Messages: 2016-03-08T18:36:25.049-08:00 [INFO] cfg_metakv: metaKVCallback, path: /fts/cbgt/cfg/indexDefs, key: indexDefs, deletion: false
2016-03-08T18:36:25.049-08:00 [INFO] ctl: kickIndexDefs, kind: cfgEvent
2016-03-08T18:36:25.080-08:00 [INFO] planner: nodesRemove: []string(nil)
2016-03-08T18:36:25.251-08:00 [INFO] planner: step planner
[goport] 2016/03/08 18:38:55 /opt/couchbase/bin/cbft terminated: signal: killed