checking in the abstractions for valid type checking:
Merge pull request #9204 from ranjaykrishna/col-prob

schema dumper tests now conducted by ActiveRecord::Base.Connection
Avoid to_sym calls
Leave Session.create responsibility to the SessionStore

[Carlos Antonio da Silva + Santiago Pastorino]
Session = Rack::Session::Abstract::SessionHash

We had already ported all the Session methods to Rack, so there's no
need to duplicate everything here.

[Carlos Antonio da Silva + Santiago Pastorino]