ensure luks temp files are cleaned up if convert_image fails

[Eric Harney]

If convert_image fails with something like this, via _encrypt_image in the RBD driver:

2019-08-29 02:22:20.413 36 DEBUG cinder.volume.drivers.rbd [req-236efa2d-8076-4f22-8326-6df4eebc0671 - -
- - -] connecting to openstack@ceph (conf=/etc/ceph/ceph.conf, timeout=-1). _do_conn /usr/lib/python3.6/s
ite-packages/cinder/volume/drivers/rbd.py:402
2019-08-29 02:22:20.540 36 DEBUG cinder.volume.drivers.rbd [req-236efa2d-8076-4f22-8326-6df4eebc0671 - -
- - -] connecting to openstack@ceph (conf=/etc/ceph/ceph.conf, timeout=-1). _do_conn /usr/lib/python3.6/s
ite-packages/cinder/volume/drivers/rbd.py:402
2019-08-29 02:22:20.658 36 DEBUG cinder.volume.drivers.rbd [req-236efa2d-8076-4f22-8326-6df4eebc0671 - -
/Traceback
...skipping
Stdout: ''
Stderr: "qemu-img: Could not open '/var/lib/cinder/conversion/tmps33yfypx.luks': Parameter 'key-secret' i
s required for cipher\n"
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils Traceback (most recent call last):
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils File "/usr/lib/python3.6/site-packages/cinder/volu
me/utils.py", line 1148, in copy_image_to_volume
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils context, volume, image_service, image_id)
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils File "/usr/lib/python3.6/site-packages/cinder/volu
me/drivers/rbd.py", line 1511, in copy_image_to_encrypted_volume
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils encrypted=True)
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils File "/usr/lib/python3.6/site-packages/cinder/volu
me/drivers/rbd.py", line 1557, in _copy_image_to_volume
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils self._encrypt_image(context, volume, tmp_dir, tm
p.name)
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils File "/usr/lib/python3.6/site-packages/cinder/volu
me/drivers/rbd.py", line 1540, in _encrypt_image
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils passphrase_file=pass_file.name)
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils File "/usr/lib/python3.6/site-packages/cinder/imag
e/image_utils.py", line 300, in convert_image
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils passphrase_file=passphrase_file)
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils File "/usr/lib/python3.6/site-packages/cinder/imag
e/image_utils.py", line 244, in _convert_image
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils utils.execute(*cmd, run_as_root=run_as_root)
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils File "/usr/lib/python3.6/site-packages/cinder/util
s.py", line 128, in execute
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils return processutils.execute(*cmd, **kwargs)
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils File "/usr/lib/python3.6/site-packages/oslo_concur
rency/processutils.py", line 424, in execute
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils cmd=sanitized_cmd)
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils oslo_concurrency.processutils.ProcessExecutionError:
 Unexpected error while running command.
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils Command: qemu-img convert -O luks -f raw -o cipher-a
lg=aes-256,cipher-mode=xts,ivgen-alg=plain64 --object secret,id=luks_sec,format=raw,file=/var/lib/cinder/
conversion/luks_tvrmcome -o key-secret=*** /var/lib/cinder/conversion/tmps33yfypx /var/lib/cinder/convers
ion/tmps33yfypx.luks
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils Exit code: 1
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils Stdout: ''
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils Stderr: "qemu-img: Could not open '/var/lib/cinder/c
onversion/tmps33yfypx.luks': Parameter 'key-secret' is required for cipher\n"
2019-08-29 05:45:46.248 36 ERROR cinder.volume.utils

The target tmps33yfypx.luks file is not removed. It needs to be removed by the RBD driver or possibly should be managed in the image_utils code.