Launch job on new cluster gives option to persist

Fixes: bug 1240928

The action of launching a job on a new cluster now gives the
user an option to have the cluster persist after the exit
of the job via a checkbox at the bottom of the cluster
creation form.

Change-Id: If8d53c3a06ee9cd9a642f2bc73ca310b4e21f159
Merge "Launch job on new cluster gives option to persist"