Clone of upstream bug.

Description of problem:
=======================
When events are stored at elasticsearch backend filtering by custom event traits is not working.

ceilometer event-list -q 'SnapshotName=TestSnapshot-2'

TransportError(400, u'SearchPhaseExecutionException[Failed to execute phase [query], all shards failed; shardFailures {[LHNt_PvMSruIUvD48176Vg][events_2015-05-14][0]: SearchParseException[[events_2015-05-14][0]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-14] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-15][0]: SearchParseException[[events_2015-05-15][0]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-15] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-18][0]: SearchParseException[[events_2015-05-18][0]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-18] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-25][0]: SearchParseException[[events_2015-05-25][0]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-25] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-14][1]: SearchParseException[[events_2015-05-14][1]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-14] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-15][1]: SearchParseException[[events_2015-05-15][1]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-15] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-18][1]: SearchParseException[[events_2015-05-18][1]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-18] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-25][1]: SearchParseException[[events_2015-05-25][1]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-25] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-14][2]: SearchParseException[[events_2015-05-14][2]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-14] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-15][2]: SearchParseException[[events_2015-05-15][2]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-15] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-18][2]: SearchParseException[[events_2015-05-18][2]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-18] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-25][2]: SearchParseException[[events_2015-05-25][2]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-25] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-14][3]: SearchParseException[[events_2015-05-14][3]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-14] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-15][3]: SearchParseException[[events_2015-05-15][3]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-15] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-18][3]: SearchParseException[[events_2015-05-18][3]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-18] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-25][3]: SearchParseException[[events_2015-05-25][3]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-25] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-14][4]: SearchParseException[[events_2015-05-14][4]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-14] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-15][4]: SearchParseException[[events_2015-05-15][4]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-15] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-18][4]: SearchParseException[[events_2015-05-18][4]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-18] [nested] nested object under path [traits] is not of nested type]; }{[LHNt_PvMSruIUvD48176Vg][events_2015-05-25][4]: SearchParseException[[events_2015-05-25][4]: from[-1],size[-1]: Parse Failure [Failed to parse source [{"query": {"filtered": {"filter": {"bool": {"must": [{"nested": {"path": "traits", "query": {"filtered": {"filter": {"bool": {"must": [{"query": {"query_string": {"query": "SnapshotName: \\"testsnapshot-2\\""}}}]}}}}}}]}}}}}]]]; nested: QueryParsingException[[events_2015-05-25] [nested] nested object under path [traits] is not of nested type]; }]') (HTTP 500) (Request-ID: req-16e9154a-c9fb-499c-bee1-b97d10c204d1)