fix `static_path` and `template_path` to be absolute
        path according to self.root_path so that PWD can be ignoreed.

def _fix_paths(self, options):
        """
        fix `static_path` and `template_path` to be absolute
        path according to self.root_path so that PWD can be ignoreed.
        """
        for k in ('template_path', 'static_path'):
            if k in options:
                v = options.pop(k)
                if v is None:
                    continue
                if not os.path.isabs(v):
                    v = os.path.abspath(
                        os.path.join(self.root_path, v))
                    app_log.debug('Fix %s to be absolute: %s' % (k, v))
                options[k] = v