Workaround logger require issues with concurrent-ruby 1.3.5 and older Rails versions

Author: chadlwilson

src/spec/ruby/spec_helper.rb

@@ -163,6 +163,7 @@ def should_not_eval_as_nil(code, runtime = @runtime) # alias
 begin
   # NOTE: only if running with a `bundle exec` to better isolate
   if $LOAD_PATH.find { |path| path =~ /\/rails\-[\w\.]*\// }
+    require 'logger' # Workaround for concurrent-ruby problems on older rails versions
     require 'rails/version' # use Rails::VERSION to detect current env
     require 'rails' # attempt to load rails - for "real life" testing
   end