Try to fix Travis build failures

In my experience bootstrap.py wants the latest setuptools and it wants a
distribute egg.  Asking for the latest distribute should give us both.

.travis.yml

@@ -11,6 +11,7 @@ before_install:
     - sudo rm -rf /dev/shm
     - sudo ln -s /run/shm /dev/shm
 install:
+    - pip install -U distribute
     - python bootstrap.py
     - bin/buildout
 script: