HDFS-5895. HDFS cacheadmin -listPools has exit_code of 1 when the command returns 0 result. Contributed by Tassapol Athiapinya.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1565440 13f79535-47bb-0310-9956-ffa450edef68