HDFS-15376. Update the error about command line POST in httpfs documentation. Contributed by bianqi.

hadoop-hdfs-project/hadoop-hdfs-httpfs/src/site/markdown/index.md

@@ -42,7 +42,7 @@ HttpFS HTTP web-service API calls are HTTP REST calls that map to a HDFS file sy
 
 * `$ curl 'http://httpfs-host:14000/webhdfs/v1/user/foo?op=GETTRASHROOT&user.name=foo'` returns the path `/user/foo/.Trash`, if `/` is an encrypted zone, returns the path `/.Trash/foo`. See [more details](../hadoop-project-dist/hadoop-hdfs/TransparentEncryption.html#Rename_and_Trash_considerations) about trash path in an encrypted zone.
 
-* `$ curl -X POST 'http://httpfs-host:14000/webhdfs/v1/user/foo/bar?op=MKDIRS&user.name=foo'` creates the HDFS `/user/foo/bar` directory.
+* `$ curl -X PUT 'http://httpfs-host:14000/webhdfs/v1/user/foo/bar?op=MKDIRS&user.name=foo'` creates the HDFS `/user/foo/bar` directory.
 
 User and Developer Documentation
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