Fix path method

Hi there.

Looking with interest at the managed_directory resource, I noticed a small bug wrt. file resources that use `path` instead of `name`.  Although this might be uncommon, it nonetheless is possible to have a resource like this:

```ruby
file "#{testdir}/e" do
  path "#{testdir}/d"
  action :touch
end
```

or even this

```ruby
log "#{testdir}/e" do
  message "hi there, i'm not a file"
  action :touch
end
```

....so looking for and at the `path` attribute seems like the right thing to do, IMHO.