Fixes two issues with the sencha created JSB:

            - All extjs urls are prefixed by ``../static`` instead of
              ``/static`` (no idea why).
            - We assume static files are served at ``/static``, but collectstatic may
              not build files in ``static/``. Therefore, we replace ``/static`` with
              the relative path to ``settings.STATIC_ROOT``.

def _cleanJsbAllClassesSection(self, config):
        """
        Fixes two issues with the sencha created JSB:

            - All extjs urls are prefixed by ``../static`` instead of
              ``/static`` (no idea why).
            - We assume static files are served at ``/static``, but collectstatic may
              not build files in ``static/``. Therefore, we replace ``/static`` with
              the relative path to ``settings.STATIC_ROOT``.
        """
        allclasses = config['builds'][0]
        for fileinfo in allclasses['files']:
            path = fileinfo['path']
            if path.startswith('..'):
                path = path[2:]
            path = path.replace('/static', self.static_root)
            fileinfo['path'] = path