[koji PATCH] add '--logfile <filename>' parameter for better logging (koji-shadow)

[Karsten Hopp]

Here's one of the patches to koji-shadow that I'm using now for quite a while.
koji-shadow prints everything to the console and it's up to the secondary arch maintainer to redirect it into a file.
This patch adds a --logfile parameter where it logs everything into a file and also prints to the console (similar to 
'... | tee logfile')

    Karsten