HDFS-6640. Syntax for MKDIRS, CREATESYMLINK, and SETXATTR are given wrongly in WebHdfs document (missed webhdfs/v1). Contributed by Stephen Chu.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1609603 13f79535-47bb-0310-9956-ffa450edef68