[koji patch] koji-shadow - show top broken packages instead of top brokendep packages

[Karsten Hopp]

Currently koji-shadows prints out the top 5 brokendep packages, which is kind of useless 
as they don't need fixing.
With this patchit prints out the top 10 broken packages, sorted by the number of packages

they are blocking from being built.
Secondary arch maintainers will know immediately which packages they should probably fix 
first without having to trace them down in the output.

     Karsten