[oozie] Support JobTracker HA in workflows

Whenever you submit a workflow through the Oozie app, it always takes one of the JT's defined in [[mapred_clusters]] and sets the jobTracker property for the workflow to that value. However, with JT HA, Oozie requires you to use the "logicaljt" entry for the jobTracker property when running the workflow. I also tried to trick Hue into thinking logicaljt was the JobTracker by setting:

[[mapred_clusters]]
[[[default]]]
jobtracker_url=logicaljt

However, this still doesn't work because Hue appends the jobtracker port when specifying the the jobTracker property for Oozie. This is fine when not using HA, but when using HA, the jobTracker property must be "logicaljt" and not "logicaljt:8021".