Hotfix/boost mapping test bug

Hi,

I realized that test was not passing on ES 1.0.0 because of the mapping returned by *esClient.getMapping* function.

The mapping between 0.9.11 and 1.0.0 has changed. See : http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/_indices_apis.html

I made this change in the test file. This function (the ES client *getMapping*) was only used here (so there should be no other surprise around this one).

Of course I passed the full tests on both ES versions.

Cheers,

Nicolas