Only run migrations that look like migrations

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3966 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/lib/active_record/migration.rb

@@ -352,7 +352,7 @@ def assert_unique_migration_version(migrations, version)
       end
 
       def migration_files
-        files = Dir["#{@migrations_path}/[0-9]*_*.rb"].sort_by do |f|
+        files = Dir["#{@migrations_path}/[0-9]+_*.rb"].sort_by do |f|
           migration_version_and_name(f).first.to_i
         end
         down? ? files.reverse : files