Fix breaking order test on 1.9.

* Test method name was very confusing, doesn't appear it should be
  preserving an order at all as it passes :pivot_order.
* Added a special case for a :pivot_order => :name as this refers to the
  Grouping name so it's passed through as-is.

lib/ruport/data/table.rb

@@ -98,6 +98,8 @@ def self.row_order_to_group_order(row_order_spec)
           }
         when NilClass
           nil
+        when :name  # Pass through :name as it's a special instruction to Grouping
+          :name
         else
           proc {|group| group[0][row_order_spec].to_s }
         end

test/table_pivot_test.rb

@@ -107,7 +107,7 @@ def test_preserves_ordering
     assert_equal(expected, pivoted)
   end
 
-  def test_preserves_ordering_on_calculated_column
+  def test_reorders_a_calculated_column_by_column_name
     table = Table('group', 'a')
     [
       [1, 1], [2, 2], [3, 3]