More Rails 4.0 upgrade changes

1. Compared existing branch with empty Rails 4.0 project and
    made changes as needed.
 2. Fix find/first warning.
 3. Fix sqlite timeout issue.
    -- config/database.yml
    -- spec/vulnerabilities/insecure_dor_spec.rb

config/boot.rb

@@ -1,4 +1,4 @@
 # Set up gems listed in the Gemfile.
 ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../../Gemfile', __FILE__)
 
-require 'bundler/setup' if File.exist?(ENV['BUNDLE_GEMFILE'])
+require 'bundler/setup' if File.exists?(ENV['BUNDLE_GEMFILE'])