bokeh/bokeh — pull request #1537 by damianavila (2014-12-10 11:27:58+00:00)
Title: Update apt-get listing because graphviz update.

TravisCI is looking for http://security.ubuntu.com/ubuntu/pool/main/g/graphviz/graphviz_2.26.3-10ubuntu1.1_amd64.deb (which doesn't exist).
It appears that graphviz was updated to graphviz_2.26.3-10ubuntu1.2_amd64.deb
Until the package index get update, let update for ourselves.