Add support for MemorySwappiness to create_host_config

[lots0logs]

No description provided.

[shin-]

Thanks!

The tests are failing because you have trailing whitespace and an indentation error in your patch. You can run make flake8 in the project's root to detect those locally.

Apart from the code style nitpicking:

• It seems the option was added in API version 1.20 - can we add a client-side check for that? Just like we do for group_add here
• The parameter should be added to the HostConfig documentation (docs/host_config.md).
• It might also be valuable to add an integration test that verifies the value we pass is reflected in the inspect_container dict.