Comment 1 for bug 1268684

Here's a patch that addresses the issue for me:

  $ schroot -c test-recommends-trusty-amd64 apt-config dump APT::Install-Recommends
  APT::Install-Recommends "0";

 I didn't expose it as a command line argument, though I could add it if it's desired; mk-sbuild already has a non-trivial amount of possible arguments, so my initial instinct was to resist the urge to add another to the pile.