Fixes broken select on find with populates

[luislobo]

I know 0.12.x is not being "worked on", but just in case anyone else is having the same issue, I'm posting it here as a PR.

So, fixes situation where Pet will return all attributes, even though you only select 'name'. Just for reference: SELECT only works on sails-mongo in 0.12.x.

Pet.find({select:['name']}).populate('owner').find().exec(console.log)

Related to
#292

[mikermcneil]

@luislobo thanks Luis!