Hook individual failure removal into multiple failure backend

Author: cehoffman

lib/resque/failure/multiple.rb

@@ -45,6 +45,10 @@ def self.clear
       def self.requeue(*args)
         classes.first.requeue(*args)
       end
+
+      def self.remove(index)
+        classes.each { |klass| klass.remove(index) }
+      end
     end
   end
-end
+end