Wrong package url when installing from source

Hi guys,

I was trying to install riak from source using your cookbook and got this error (ubuntu precise):

https://gist.github.com/3845225

Basically, the recipe creates the following url:

    http://s3.amazonaws.com/downloads.basho.com/riak/1.2/1.2.0/riak_1.2.0.tar.gz

Which doesn't exist. I looked into your [downloads](http://basho.com/resources/downloads/) page and the url should be:

    http://s3.amazonaws.com/downloads.basho.com/riak/1.2/1.2.0/riak-1.2.0.tar.gz

The difference is in the name of the file: `-` instead of `_`.

On another note, I had to include `package "erlang-reltool"` for it to work. Is this something that should be included in the default recipe, or should it actually be in the erlang cookbook?

Thanks,
  Carlos