HDFS-4943. WebHdfsFileSystem does not work when original file path has encoded chars. Contributed by Jerry He and Robert Parker.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1504296 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/branch-0.23' into branch-0.23-gd
Merge remote branch 'origin/branch-0.23-gd' into fb-YAHOO-218-branch-0.23-gd