Ticket 49402 - Adding a database entry with the same database name that was deleted hangs server at shutdown
    
    Bug Description:  At shutdown, after a backend was deleted, which also had a import
                      task run, the server hangs at shutdown.  The issue is that the
                      import task destructor used the ldbm inst struct to see if it was
                      busy, but the inst was freed and the destructor was checking invalid
                      memory which caused a false positive on the "busy" check.
    
    Fix Description:  Do not check if the instance is busy to tell if it's okay to remove
                      the task, instead just check the task's state.
    
    https://pagure.io/389-ds-base/issue/49402
    
    Reviewed by: lkrispen(Thanks!)
    
    (cherry picked from commit bc6dbf15c160ac7e6c553133b2b936a981cfb7b6)
    (cherry picked from commit 2ef4e813b8f6b92908ff553a704808cbbd425b5d)