The ``silent`` keyword argument to Config.from_envvar was not being honored if the environment variable existed but the file that it mentioned did not. The fix was simple - pass the keyword argument on to the underlying call to ``from_pyfile``. I also noticed that the return value from ``from_pyfile`` was not being passed back so I fixed that as well.
Requested by @plaes on #pocoo irc.
Provide a full example as promised in the doc.