Let render_file match any resource that matches path (#858)

[adsr]

While testing a recipe with something like this:

template path do
  only_if { cond }
  ...
end

file path do
  not_if { cond }
  action :delete
end

When cond was true, RenderFileMatcher was not matching because the file resource would supersede the template resource.

The patch makes it so any (cookbook_file|file|template) resource that matches the given path and content will satsify the assertion.

Fixes #858

[tpowell-progress]

@adsr if you are still interested in getting this merged, please resubmit to chef/chefspec