Replace remaining wait_idles with sleeps
    
    wait_idle is finally removed upstream in recent git os-autoinst.
    This replaces all remaining wait_idles with sleeps, except for
    one which is removed (I'm hoping improvements to typing in the
    last few years should mean it isn't necessary any more, if it
    turns out to be, I'll put it back as a sleep).
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>