Add all attribute available to LWRP to allow for tuning.

I spoke with @someara on IRC regarding some similar issues that are
fixed in the [PR][1] that I submitted earlier today. This is to bring
them up to speed so we can tune with node attributes.

[1]: https://github.com/opscode-cookbooks/yum/pull/87
Merge pull request #4 from johnbellone/master

Add all attribute available to LWRP to allow for tuning.