knetwalk bug fix

[Hatto von Hatzfeld]

It seems that knetwalk has not be maintained for a longer time.

There is a bug which makes defect a quite essential function of this game. I'd 
like someone to (review and) integrate my bugfix into the source.

See https://bugs.kde.org/show_bug.cgi?id=348686

By the way: On 
https://bugs.kde.org/buglist.cgi?bug_status=UNCONFIRMED&list_id=1412543&product=knetwalk&query_format=advanced 
there are some more bug reports which could be closed.

Thanks,
Hatto von Hatzfeld