Escape file paths for globbing

Fixes https://github.com/opscode/chef/issues/2078, replaces https://github.com/opscode/chef/pull/2087.

@opscode/client-engineers 
With PathHelper introducing a glob method, should we even show an example with Dir.glob as above?  If the PathHelper.glob method is all the functionality of Dir.glob without any of the bugs, it seems we would want people to use that.