[oozie] Fix workflow graph rendering with Python 3 (#1262) (#1266)
[oozie] Fix workflow graph rendering with Python 3 (#1262) (#1266)

* [oozie] Fix workflow graph rendering with Python 3 (#1262)

When an header like "<?xml version="1.0" encoding="UTF-8"?>" is used
at the top of an Oozie workflow, the etree.fromstring() function refuses
to work since the workflow_definition variable is not encoded.

* [oozie] Fix linter errors in workflows.py (#1262)
cloudera/hue,cloudera/hue,kawamon/hue,kawamon/hue,cloudera/hue,kawamon/hue,cloudera/hue,kawamon/hue,kawamon/hue,kawamon/hue,cloudera/hue,kawamon/hue,kawamon/hue,kawamon/hue,cloudera/hue,kawamon/hue,cloudera/hue,cloudera/hue,cloudera/hue,kawamon/hue,cloudera/hue,kawamon/hue,cloudera/hue,cloudera/hue,cloudera/hue,kawamon/hue,kawamon/hue,cloudera/hue,cloudera/hue,kawamon/hue,cloudera/hue,cloudera/hue,kawamon/hue,kawamon/hue,cloudera/hue,kawamon/hue