simple patch to avoid having to use screen's logging capabilities. Makes running koji-shadow better scriptable

• please move the "top broken" change into a separate pull request
• can't some python logging library be used instead of dealing with open/write/close directly?

There's a new pull request for the topbroken changes. I'll redo the logfile patch.

I thought about using the logging module, but tbh, that's like using a sledgehammer to crack a nut. We don't need those capabilities here.

@karsten should this PR be closed, then? Or, are you going to rebase to remove the topbroken changes here?

I've removed the topbroken changes from the logfile branch.

Commit 61db89ca fixes this pull-request