[ruby/csv] Don't change initialize_copy's return value

cf3b60db1c

lib/csv/row.rb

@@ -49,8 +49,9 @@ class CSV
     def_delegators :@row, :empty?, :length, :size
 
     def initialize_copy(other)
-      super
+      super_return_value = super
       @row = @row.collect(&:dup)
+      super_return_value
     end
 
     # Returns +true+ if this is a header row.