Clean the disk before flushing the new image.

        See: https://bugs.launchpad.net/ironic-lib/+bug/1550604

def patch_ironic_ramdisk(self):
        """Clean the disk before flushing the new image.

        See: https://bugs.launchpad.net/ironic-lib/+bug/1550604
        """
        tmpdir = self.run('mktemp -d')[0].rstrip('\n')
        self.run('cd {tmpdir}; zcat /home/stack/ironic-python-agent.initramfs| cpio -id'.format(tmpdir=tmpdir))
        self.send_file(pkg_data_filename('static', 'ironic-wipefs.patch'), '/tmp/ironic-wipefs.patch')
        self.run('cd {tmpdir}; patch -p0 < /tmp/ironic-wipefs.patch'.format(tmpdir=tmpdir))
        self.run('cd {tmpdir}; find . | cpio --create --format=newc > /home/stack/ironic-python-agent.initramfs'.format(tmpdir=tmpdir))