Code review comment for lp:~allenap/launchpad/packages-for-autoload-bug-443061

Max Bowsher said "The problem with recommending that people install the system package of lazr.uri is that it breaks launchpad dev". I asked him later to elaborate:

<maxb> So the problem is that setuptools installs a *-nspkg.pth file
  which registers the toplevel lazr package with a __path__ pointing
  to the system directory
<maxb> This defeats attempts to add any other lazr.* via PYTHONPATH
<maxb> And then you have a bit of a conundrum. I haven't figured out
  how to solve it, or if it is soluble
<allenap> maxb: Ah, that's grizzly. If it's installed via a deb then
  this won't be a problem, will it? Not that there's a lazr.uri deb
  easily available.
<maxb> Yes, it is a problem, and there's lazr.something debs available
  in karmic, hence me noticing the problem
<maxb> python-lazr-uri | 1.0-0ubuntu1 | karmic | all

I changed the warning message to recommend against any system-wide
installation of these packages, rather than just pointing the finger
at setuptools.