Fix for issue #29

(GH-29) Add additional default installation path for chocolatey

chocolatey 0.9.8.24 comes with new installation path -
C:\ProgramData\chocolatey. When you install this version of chocolatey
and use the provider in the same puppet run you will get an error
message saying that the provider is not functional on this host.

This change addresses the issue by checking if the legacy installation path
is present. If it is not it defaults to the new installation path to
avoid breaking the provider for older versions of chocolatey.