Initialize/update our mock chroot

def init_mock(self, release):
        """Initialize/update our mock chroot"""
        root = '/var/lib/mock/%s' % release['mock']
        if not os.path.isdir(root):
            self.mock_cmd(release, '--init')
            self.log.info('mock chroot initialized')
        else:
            if release.get('mock_clean'):
                self.mock_cmd(release, '--clean')
                self.mock_cmd(release, '--init')
                self.log.info('mock chroot cleaned & initialized')
            else:
                self.mock_cmd(release, '--update')
                self.log.info('mock chroot updated')