[SPARK-13933][BUILD] Update hadoop-2.7 profile's curator version to 2.7.1

## What changes were proposed in this pull request?

Update hadoop-2.7 profile's curator version to 2.7.1, more see [SPARK-13933](https://issues.apache.org/jira/browse/SPARK-13933).

## How was this patch tested?

manual tests

Author: Yuming Wang <wgyumg@gmail.com>

Closes #18247 from wangyum/SPARK-13933.

dev/deps/spark-deps-hadoop-2.7

@@ -47,9 +47,9 @@ commons-net-2.2.jar
 commons-pool-1.5.4.jar
 compress-lzf-1.0.3.jar
 core-1.1.2.jar
-curator-client-2.6.0.jar
-curator-framework-2.6.0.jar
-curator-recipes-2.6.0.jar
+curator-client-2.7.1.jar
+curator-framework-2.7.1.jar
+curator-recipes-2.7.1.jar
 datanucleus-api-jdo-3.2.6.jar
 datanucleus-core-3.2.10.jar
 datanucleus-rdbms-3.2.9.jar

pom.xml

@@ -2532,6 +2532,7 @@
       <id>hadoop-2.7</id>
       <properties>
         <hadoop.version>2.7.3</hadoop.version>
+        <curator.version>2.7.1</curator.version>
       </properties>
     </profile>