ipatests: fix tests in TestACMEPrune
    
    When cron_minute + 5 > 59, cron job throwing error for it.
    i.e 58 + 5 = 63 which is not acceptable value for cron minute.
    
    Second fix is related to mismatch of confing setting and corresponding
    assert.
    
    Third fix is related to extending time by 60 minutes to properly
    expire the certs.
    
    related: https://pagure.io/freeipa/issue/9294
    
    Signed-off-by: Mohammad Rizwan <myusuf@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>