Fixes
```
======================================================================
ERROR: setUpClass (ssh_test.BannerTest)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/vsts/work/1/s/tests/testlib.py", line 625, in setUpClass
cls.dockerized_ssh = DockerizedSshDaemon(**daemon_args)
File "/home/vsts/work/1/s/tests/testlib.py", line 553, in __init__
self.start_container()
File "/home/vsts/work/1/s/tests/testlib.py", line 533, in start_container
self._get_container_port()
File "/home/vsts/work/1/s/tests/testlib.py", line 510, in _get_container_port
self.port = int(bport)
ValueError: invalid literal for int() with base 10: ':]:32770'
```
To do so the test suite allows a weak cryptographic alogorithm (SHA1) to be
used, principally for CentOS 6 targets. This can be removed if/when support
for older (legacy) targets is dropped.
Only the test suite enables this known weak alogorithm. Mitogen as-shipped
doesn't enable or disable algorithms.
A few changes are bundled in this
- Ansible 2.10.x and Mitogen 0.3.x are used to build nearly all images
(Ansile 2.3.x is retained for CentOS 5, because it uses Python 2.4).
- Tox is used to install/run Ansible, replacing build_docker_images.py
- A static inventory, identifying containers by name rather than ID.
- debian-test image is renamed to debian9-test
- debian9-test image is now based on debian:9
- centos6-test image is now based on moreati/centos6-vault
following the same scheme as centos5-test.
- Images are now uploaded to Amazon Elastic Container Registry (ECR).
See #809.
- Debian recommended packages aren't installed (e.g. build-essential)
- Python 2.x and Python 3.x are installed wherever available.
- Python Virtualenv is installed wherever available.
This relies on the previous commit resetting global variables.
Update clean_shutdown() to handle duplicate calls, due to tests
repeatedly installing it.