Code review comment for lp://staging/~javier.collado/utah/bug1152216

I still get
bzr: ERROR: Not a branch: "/home/max/bzr/build/utah/".
but the imports work now. I'm not sure if we want to be passing that error through. If I set stderr to open('/dev/null', 'w') in the check_output call, it suppresses the output. If you think it makes sense to have that output, I'm fine either way.