Comment 5 for bug 1836041

Here's my proposed fix for the Xenial tree. I was able to verify that the 'all' target works as expected in a pristine Xenial amd64 VM using the following command:

  $ sudo make KERNEL=linux-pc-image MIRROR=us.archive.ubuntu.com DESTDIR=dest all

I compared the output of that command with and without my patch applied to verify that no unauthenticated repositories/packages are being used once that patch is applied.