handle local password policies
comments are always good.

It's tough to understand this fix, thus putting some descriptive
comments.
Clarify comments on Windows API behavior with direct link to documentation
Merge pull request #855 from opscode/adamed-8391-password-policy

OC-8391: Chef::Provider::User::Windows fails with local password policies
CHEF-4314: Pin active_support < 4.0.0 due to atomic + CAS issues