Fixed "can't convert Fixnum into String" error on projects with numerical identifier (#10135).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@8804 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/project.rb

@@ -274,7 +274,7 @@ class Project < ActiveRecord::Base
 
   def to_param
     # id is used for projects with a numeric identifier (compatibility)
-    @to_param ||= (identifier.to_s =~ %r{^\d*$} ? id : identifier)
+    @to_param ||= (identifier.to_s =~ %r{^\d*$} ? id.to_s : identifier)
   end
 
   def active?