blockbox lvm-debian-cinder container fails

[Noel McLoughlin]

I'm using "generic/ubuntu1804" vagrant image, cloning cinder, making blockbox and running docker-compose successfully - however the `lvm-debian-cinder` and `cinder-scheduler` containers are failing with an bug https://bugs.python.org/issue31652-

```
ImportError: No module named _ctypes
/scripts/lvm-service.sh: line 3: YUM: command not found
/scripts/lvm-service.sh: line 4: APT: command not found
Traceback (most recent call last):
  File "/var/lib/openstack/bin/cinder-volume", line 6, in <module>
    from cinder.cmd.volume import main
  File "/var/lib/openstack/lib/python2.7/site-packages/cinder/__init__.py", line 21, in <module>
    import eventlet # noqa
  File "/var/lib/openstack/lib/python2.7/site-packages/eventlet/__init__.py", line 24, in <module>
    import monotonic
  File "/var/lib/openstack/lib/python2.7/site-packages/monotonic.py", line 50, in <module>
    import ctypes
  File "/usr/lib/python2.7/ctypes/__init__.py", line 7, in <module>
    from _ctypes import Union, Structure, Array
ImportError: No module named _ctypes
```

I will retry with different image - its related to missing libffi-devel when python is built.

[Noel McLoughlin (noelmcloughlin)]

I tested again (vagrant "ubuntu/bionic64" box) running these commands first.
```
yum check-update -y || apt-get update -y
yum install git libffi-devel -y || apt-get install git libffi-dev -y
```

The issue is gone.
The package `libffi-dev` (Ubuntu) and `libffi-devel` (RedHat) are prequisites.