Ticket 51 - Job rearm should ignore if ns_persist is set
    
    Bug Description:  If a job is persistent, and we rearm it, it's added to the
    event queue twice. This can cause bugs where there is not enough io to satisfy
    the job.
    
    Fix Description:  If a job is persistent, ignore it in rearm.
    
    https://fedorahosted.org/nunc-stans/ticket/51
    
    Author: wibrown
    
    Review by: nhosoi (Thanks!)