Create PATH_DISTS and PATH_LOG.

To alleviate these errors:

salt:/home/vagrant # /usr/local/pythonz/bin/pythonz install 2.7.3
Downloading Python-2.7.3.tgz as /root/.pythonz/dists/Python-2.7.3.tgz

ERROR: Failed to download.
Failed to fetch /root/.pythonz/dists/Python-2.7.3.tgz from http://www.python.org/ftp/python/2.7.3/Python-2.7.3.tgz
salt:/home/vagrant #

---

salt:/home/vagrant # /usr/local/pythonz/bin/pythonz install 2.7.3
Downloading Python-2.7.3.tgz as /root/.pythonz/dists/Python-2.7.3.tgz
########################################################################## 100%
Extracting Python-2.7.3.tgz into /root/.pythonz/build/CPython-2.7.3

This could take a while. You can run the following command on another shell to track the status:
  tail -f /root/.pythonz/log/build.log

Installing CPython-2.7.3 into /root/.pythonz/pythons/CPython-2.7.3
Traceback (most recent call last):
  File /usr/local/pythonz/scripts/pythonz/installer/pythoninstaller.py, line 183, in install
    self.configure()
  File /usr/local/pythonz/scripts/pythonz/installer/pythoninstaller.py, line 303, in configure
    s.check_call(cmd)
  File /usr/local/pythonz/scripts/pythonz/util.py, line 292, in check_call
    returncode = self.call(cmd)
  File /usr/local/pythonz/scripts/pythonz/util.py, line 274, in call
    fp = ((self._log and open(self._log, 'a')) or None)
IOError: [Errno 2] No such file or directory: '/root/.pythonz/log/build.log'
ERROR: Failed to install CPython-2.7.3. Check /root/.pythonz/log/build.log to see why.
salt:/home/vagrant
Merge pull request #27 from holmboe/master

Create PATH_DISTS and PATH_LOG directories