Clean up HdfsBrowserServlet and make it possible to check for file access issues when checking viewer capabilities.
Fix NullPointerException in SequenceFileReader caused by AzkabanSequenceFileReader suppressing IOException in AzkabanSequenceReader.Reader's constructor.
Surround body of handleAjaxAction in a try/finally. Fix no_fs in HDFS file page.
Indentation changes.
Merge pull request #87 from davidzchen/hdfs-perm-error

HDFS Viewer displays "error: null" when permission is denied