raise the same exception in order to keep path info

Ruby 2.0.0 implements LoadError#path, but newly raised load errors will
not contain the path information.  Replace the error message, copy
blame, and rereaise the same exception object

activesupport/lib/active_support/dependencies.rb

@@ -305,7 +305,8 @@ def depend_on(file_name, message = "No such file to load -- %s.rb")
       require_or_load(path || file_name)
     rescue LoadError => load_error
       if file_name = load_error.message[/ -- (.*?)(\.rb)?$/, 1]
-        raise LoadError.new(message % file_name).copy_blame!(load_error)
+        load_error.message.replace(message % file_name)
+        load_error.copy_blame!(load_error)
       end
       raise
     end

activesupport/test/dependencies_test.rb

@@ -39,6 +39,19 @@ def with_autoloading_fixtures(&block)
     with_loading 'autoloading_fixtures', &block
   end
 
+  def test_depend_on_path
+    skip "LoadError#path does not exist" if RUBY_VERSION < '2.0.0'
+
+    expected = assert_raises(LoadError) do
+      Kernel.require 'omgwtfbbq'
+    end
+
+    e = assert_raises(LoadError) do
+      ActiveSupport::Dependencies.depend_on 'omgwtfbbq'
+    end
+    assert_equal expected.path, e.path
+  end
+
   def test_tracking_loaded_files
     require_dependency 'dependencies/service_one'
     require_dependency 'dependencies/service_two'