Escape file paths for globbing

Fixes https://github.com/opscode/chef/issues/2078, replaces https://github.com/opscode/chef/pull/2087.

@opscode/client-engineers 
do you also want to run this through cleanpath()

sorta where i'm going is that it looks like join() uses windows path seps on windows, and if we're going to go to that trouble we should cleanpath() it as well.  if we're not going to fully go to that trouble, then we can just join('/') the paths with unix/ruby path seps...