Pass the order option as an array to satisfy sqlserver adapter (#12713).

Unlike other adapters, the sqlserver adapter processes the order option and wipes it when using functions.
Here we can see a "ASC" inserted in the COALESCE call:

irb(main):001:0> Issue.order("coalesce(estimated_hours, 0), id").to_sql
=> "SELECT [issues].* FROM [issues] ORDER BY coalesce(estimated_hours ASC, 0) ASC, id ASC"

This does not happen when passing the order SQL fragments separately.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11115 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/helpers/sort_helper.rb

@@ -80,12 +80,13 @@ module SortHelper
       @criteria.collect {|k,o| k + (o ? '' : ':desc')}.join(',')
     end
 
+    # Returns an array of SQL fragments used to sort the list
     def to_sql
       sql = @criteria.collect do |k,o|
         if s = @available_criteria[k]
-          (o ? s.to_a : s.to_a.collect {|c| append_desc(c)}).join(', ')
+          (o ? s.to_a : s.to_a.collect {|c| append_desc(c)})
         end
-      end.compact.join(', ')
+      end.flatten.compact
       sql.blank? ? nil : sql
     end