Ticket 47451 - Running a plugin task can crash the server
    
    Bug Description:  When a plugin task completes it attempts to update a counter,
                      but the wrong structure is accessed which can lead to a crash.
    
    Fix Description:  When creating a new task, make sure to store the plugin structure,
                      not the pblock in the task structure.
    
    https://fedorahosted.org/389/ticket/47451
    
    Reviewed by: rmeggins(Thanks!)