Clean the "uploading" state for failed post uploads or app crash

In some cases [PostUploadService.onDestroy()](https://github.com/wordpress-mobile/WordPress-Android/blob/7660b98cd2a7e8ac5c4104827bb8d4796be3541b/WordPress/src/main/java/org/wordpress/android/ui/posts/PostUploadService.java#L92-L100) is not called, and a post could be stuck in "uploading" state.

It's tricky but we must find a way to clean this state in some cases on PostsList onCreate.
