docs: “View source” buttons in the API reference are linked to 404 page (again)

[yuasakusa]

Steps to reproduce:

1. Open a page in the API reference on docs.angularjs.org, e.g. http://docs.angularjs.org/api/ng.$http
2. Click the “View source” button.

Actual result:
Page https://github.com/angular/angular.js/tree/v1.2.7-build.2036+sha.e415e91/src/ng/http.js#L173 is opened, but it is 404.

Expected result:
A correct page (probably https://github.com/angular/angular.js/tree/e415e91/src/ng/http.js#L173) should be opened.

Note:
The issue is similar to issue #3616. Also issue #4904 appears to be related.

[bcronje]

+1 Not having the "View source" button work correctly is a real pain.

[yuasakusa]

Thank you for fixing!