message: elasticsearch version 5.3.2 -> 5.1.2
diff: <java.version>1.8</java.version>
  <skipTests>true</skipTests>
  <lucene.version>6.4.2</lucene.version>
  - <elasticsearch.version>5.3.2</elasticsearch.version>
  + <elasticsearch.version>5.1.2</elasticsearch.version>
  </properties>
  <dependencies>
  <dependency>
  <groupId>org.nlpcn</groupId>
  <artifactId>elasticsearch-sql</artifactId>
  - <version>5.3.2.0</version>
  + <version>5.1.2.0</version>
  </dependency>
  <dependency>
  <groupId>org.elasticsearch.client</groupId>
  