.travis.yml: Remove PYTHONPATH and sudo from 'make setup'

The Travis runs currently die with:

    Traceback (most recent call last):
      File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/nose/loader.py", line 414, in loadTestsFromName
        addr.filename, addr.module)
      File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/nose/importer.py", line 47, in importFromPath
        return self.importFromDir(dir_path, fqname)
      File "/home/travis/virtualenv/python2.7.8/lib/python2.7/site-packages/nose/importer.py", line 94, in importFromDir
        mod = load_module(part_fqname, fh, filename, desc)
      File "/home/travis/build/thumbor/thumbor/thumbor/integration_tests/__init__.py", line 3, in <module>
        from tornado.testing import AsyncHTTPTestCase
    ImportError: No module named tornado.testing

But we are installing Tornado.  This commit simplifies what we're
doing to try and get successful tests with less magic.

There's also a debugging printout to figure out which Tornado we're
using, so don't merge this until we get a successful test and I rebase
that print back out ;).