Tidy up api client registration specs
Add optional client-side key generation when registering
Add new config option to DOC_CHANGES
Merge branch 'CHEF-4373'
Fix unit tests to not access /etc/chef/encrypted_data_bag_secret
[CHEF-5150] chef-service-manager: don't create interactive service

See http://msdn.microsoft.com/en-us/library/windows/desktop/ms683502%28v=vs.85%29.aspx
Default value in win32-service is interactive and there is no reason why
chef-client should run as that.