Jar upload directory not created

Steps to reproduce:

• setup configuration property: jobmanager.web.tmpdir = /mnt/flink/web
• this directory should not exist
• Run flink job manager.
• in logs:

  2017-05-11 12:07:58,397 ERROR org.apache.flink.runtime.webmonitor.WebMonitorUtils           - WebServer could not be created [main]
  java.io.IOException: Jar upload directory /mnt/flink/web/flink-web-3f2733c3-6f4c-4311-b617-1e93d9535421 cannot be created or is not writable.
  

Expected:

• create parent directories if they do not exit. i.e. use "uploadDir.mkdirs()" instead of "uploadDir.mkdir()"

Note:

• BlobServer create parent directories (See BlobUtils storageDir.mkdirs())