Code review comment for lp:~cwarner/unattended-upgrades/whitelisting

Thanks for this branch! It looks good overall, some made some comments inline.

One issue right now is that the tests need a update, i.e.:
$ (cd tests ; make)
fails right now and there is no test that checks if the whitelisting works.

It also seems that the test for the whitelisted strings needs to check if there are only whitelisted packages in the upgrade set to ensure that there is no package that is pulled in via a dependency there (unless that is not what you want).

I pushed lp:~mvo/unattended-upgrades/whitelisting with the test fixes and the whitelist verification changes. Please have a look and merge if it seems sensilble.