Versioning is always unlimited regardless of the configuration

[gdelaporte]

Trying to set the max number of versions for an object, in the namespace configuration or forcing it at the container level, the number of versions is always unlimited.

[fvennetier]

After PR #1250, versioning is still not enforced, but you can purge exceeding versions by running openio container purge. I see 3 possible evolutions:

1. refuse to add a new version when the limit is reached;
2. purge oldest versions on-the-fly (this is the original behavior);
3. keep the code as-is, and let the Lifecycle crawler purge the oldest versions.