IDL: Overwrite pickle file when an exception occurs

It seems that TypeErrors can be thrown when we modify the content of
pickle files (e.g. InterfacesInfoCoreIndividual.pickle). We can
just overwrite pickle files if pickle.load() throws an exception.

Review URL: https://codereview.chromium.org/643153006

git-svn-id: svn://svn.chromium.org/blink/trunk@184334 bbb929c8-8fbe-4397-9dbb-9b2b20218538