Bump chef-client version to 11.12.2

I'd like to bump the version of chef-client here to the current latest so it can be included with the upcoming OSC release. If this is a problem for some reason, let me know. 

The reason is that a user is doing something strange that is hitting the embedded chef-client and is encountering a bug that exists in 11.10 but is fixed in 11.12. Should they be doing strangeness? Probably not, but it's not a bad idea to update the client version here.