Compatibility with pytest 3.4
    
    The nose_compat plugin uses internal pytest APIs to suspend and resume
    the capture manager. In pytest 3.4, the internal APIs have changed and a
    public API was added.
    
    The fix is required to run integration tests under Fedora 28.
    
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>