Reset Chef::Config in org restore so it uses the pivotal key

ChefFS::Config.new will check values in Chef::Config, because we
mutate state in Chef::Config it's necessary to reset some values
in Chef::Config then instantiate a new ChefFS::Config object.
Merge pull request #27 from opscode/pwm/clients-error

Reset Chef::Config in org restore so it uses the pivotal key for the admins group