Couple of small patches related to the critpath scripts

[Pierre-Yves Chibon]

Hi,

Here are two small patch for the releng repo.

The first one is just some cosmetic changes to the critpath.py script, the
second is more interesting as it reduces the number of calls made by the
update-critpath script since the pkgdb2 API is able to handles a query about
multiple packages at once.
This should speed up the update-critpath script quite a bit.


Thanks,
Pierre