test nbextensions_configurator with non-valid yaml files
test nbextensions_configurator with non-valid yaml files

original-commit-id: 86daeb4b1b50a2d1dfe07d26501a9394e41a4517
original-commit-url: https://github.com/ipython-contrib/IPython-notebook-extensions/commit/86daeb4b1b50a2d1dfe07d26501a9394e41a4517

jcb91/jupyter_nbextensions_configurator,jcb91/jupyter_nbextensions_configurator,jcb91/jupyter_nbextensions_configurator,jcb91/jupyter_nbextensions_configurator