Use ab_user instead of session to pull active_experiments

Author: andrehjr

lib/split/analytics.rb

@@ -31,10 +31,10 @@ def tracking_code(options = {})
     end
 
     def custom_variables
-      return nil if session.nil?
+      return nil if ab_user.nil?
       arr = []
 
-      session.each_with_index do |h, i|
+      ab_user.active_experiments.each_with_index do |h, i|
         arr << "_gaq.push([\"_setCustomVar\", #{i + 1}, \"#{h[0]}\", \"#{h[1]}\", 1]);"
       end
       arr.reverse[0..4].reverse.join("\n")