Comment 7 for bug 1698551

Just hit this when trying to build a fedora-atomic image.

disk-image-create fedora-atomic -o fedora-atomic

Following the instructions on magnum repo: https://github.com/openstack/magnum/tree/master/magnum/drivers/common/image/fedora-atomic

Fails with:

2017-10-31 00:10:56.032 INFO diskimage_builder.block_device.level3.mount [-] Called for [mount_mkfs_root]
2017-10-31 00:10:56.032 INFO diskimage_builder.block_device.utils [-] Calling [sudo umount /tmp/dib_build.Ov21ervR/mnt/]
Traceback (most recent call last):
  File "/home/fedora/bin/dib-block-device", line 11, in <module>
    sys.exit(main())
  File "/home/fedora/lib/python2.7/site-packages/diskimage_builder/block_device/cmd.py", line 120, in main
    return bdc.main()
  File "/home/fedora/lib/python2.7/site-packages/diskimage_builder/block_device/cmd.py", line 115, in main
    self.args.func()
  File "/home/fedora/lib/python2.7/site-packages/diskimage_builder/block_device/cmd.py", line 39, in cmd_umount
    self.bd.cmd_umount()
  File "/home/fedora/lib/python2.7/site-packages/diskimage_builder/block_device/blockdevice.py", line 420, in cmd_umount
    node.umount()
  File "/home/fedora/lib/python2.7/site-packages/diskimage_builder/block_device/level3/mount.py", line 98, in umount
    exec_sudo(["umount", self.state['mount'][self.mount_point]['path']])
  File "/home/fedora/lib/python2.7/site-packages/diskimage_builder/block_device/utils.py", line 125, in exec_sudo
    ' '.join(sudo_cmd))
subprocess.CalledProcessError: Command 'sudo umount /tmp/dib_build.Ov21ervR/mnt/' returned non-zero exit status 32