Added name attribute

There are trouble bringing up a machine vith vagrant+vagrant-berkshelf plugin. The error is the same than https://github.com/librato/papertrail-cookbook/commit/3f0beff79811e9cecee1289981d745a4ef2cfcb8
I had the same error on my machine recently
Update metadata.rb

I messed up with the previous commit
Merge pull request #2 from c-castillo/master

Added name attribute to metadata.rb