Ensure JIRA class has _rank field
Ensure JIRA class has _rank field

Was previously only defined when using deprecated GreenHopper
class.

dwmarshall/pycontribs-jira,pycontribs/jira,stevencarey/jira,stevencarey/jira,dwmarshall/pycontribs-jira,milo-minderbinder/jira,pycontribs/jira,milo-minderbinder/jira