fix(angular.js): wrong $httpBackend status code

If I run html document as a file in browser (e.g. file:///index.html), then all ajax responses have a protocol "file" (and therefore response status code can be 200 or 404)
```
(protocol == 'file') ? (response ? 200 : 404)
```
locationProtocol has higher priority in completeRequest function.

It's critical in mobile hybrid applications which use angularjs (index.html run from local filesystem)