Enable Windows services to run as a different user (CHEF-4921). This adds :run_as_user and
:run_as_password attributes to the windows_service resource. If a logon user is specified,
the resource will (on every run) grant the logon-as-service privilege to that user, using
secedit.exe.
Merge pull request #2288 from opscode/cdoherty-enhance-win-service

Enable logon-as-service in windows_service (CHEF-4921).