oozie.coord.actions.default.length and latest coordinator displayed actions

Oozie configuration can have 'oozie.coord.actions.default.length' parameter which overloads oozie 'len' param, and Hue may not display latest coordinator actions if they are exceeding this value. Since https://issues.apache.org/jira/browse/OOZIE-1754 oozie can sort coordinator actions.
We need to request oozie to sort coordinator actions in descending order and display them correctly by dashboard.py.