Fix sphinx environment.py; needed when sphinx complains about number of arguments to find_files

fix_sphinx_environment.md

Locate find_files line and modify it to match:

        def find_files(self, config, builder=None)

Also search for the lines where find_files is invoked; and assure we have a second argument (None)

        # the source and doctree directories may have been relocated
        self.srcdir = srcdir
        self.doctreedir = doctreedir
        self.find_files(config, None)
        self.config = config