Reviewed by Dan Bernstein.

        Crash when a plug-in tries to load a resource from the application cache
        https://bugs.webkit.org/show_bug.cgi?id=60735
        <rdar://problem/8216142>

        When loading application cache resources from disk, we would never restore the
        HTTP status code, which means that resources would always have a 0 status code.
        This led to the plug-in stream loader canceling the load, something which the application
        cache loading machinery couldn't deal and thus would crash.

        Fix the reading of the HTTP status code, and make the loader more robust against
        application cache loads being canceled.

        Unfortunately, I couldn't come up with a test for this because I couldn't find a reliable way
        to force the application cache to be read from disk, so all resources would have valid values.

        * loader/DocumentLoader.cpp:
        (WebCore::DocumentLoader::substituteResourceDeliveryTimerFired):
        * loader/appcache/ApplicationCacheStorage.cpp:
        (WebCore::ApplicationCacheStorage::loadCache):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@86397 268f45cc-cd09-0410-ab3c-d52691b4dbfc