upgrade the six for ubuntu-14.04 #7

fix problem of the `pkg_resources.VersionConflict`.

```
pkg_resources.VersionConflict: (six 1.5.2 (/usr/lib/python2.7/distribution-packages), Requirement.parse('six>=1.6.0'))
```

Author: chusiang

setup_jupyter.yml

@@ -126,7 +126,10 @@
       when:
         - ansible_pkg_mgr == "portage"
 
-    # Only install Jupyter.
+    # install Jupyter.
+    - name: upgrade the six
+      pip: name=six state=latest
+
     - name: install the jupyter notebook
       pip: name=jupyter version=1.0.0 state=present