Remove undocumented, unnecessary const_missing_from_s3_library that broke my UserBucket model.

Hi Marcel,

I found this comment from you on the web:

"
Just to sanity check, you could go into lib/aws/s3/extensions.rb and 
remove
the definition to const_missing_from_s3_library and the two calls to
alias_method below it. I threw in that const missing recently just to 
add a
tiny convenience to the API. What it provides isn't even documented and 
the
library doesn't depend on it so you can safely take it away. I probably 
will
remove it. I was just trying it on to see how it felt. But either way, 
my
const_missing shouldn't be getting in the way since it's chaining back 
to the
original.
"

Source: http://www.ruby-forum.com/topic/89681

This little "convenience" led me on quite the interesting wild goose chase. I have a Rails model named Bucket and it is mapped by an association table to the User model. That association's name? UserBucket. Yeah, well, adding aw-s3 to my Gemfile caused all sorts of interestingly broken behavior. Since you yourself suggested that you may remove it, I've taken the liberty of doing it for you :-)

Thanks!
Brandon