Skip RootPropertiesShouldSerialize test on ES 1.2.0 (https://github.com/elasticsearch/elasticsearch/pull/6353)
Remove unnecessary/bad index call that causes test to hang on 1.1.2
Manually map histogram aggregation item to support ES 1.2 response as well as 1.1 and 1.0
Skip tests for aggregations that don't exist in ES 1.0
currentVersion field should be private