RUBY-632 correcting apache 2.0 license compliance

I'm repeating the same process here that I just went through on the MongoDB Ruby driver to shore up our Apache 2.0 license requirements. We were missing a few items and had a few other things done incorrectly.

These fixes bring us inline with what the ASF requires of us when licensing our software under Apache 2.0 and these fixes will make our package maintaining friends a lot happier.