<rdar://problem/4758919> - Incorrect favicon shown for URL after going back

        When restoring a cached page, we'd try to kick off the icon load for it, which ended up causing 
        shenanigans with the icon url -> page url mapping.  

        * loader/FrameLoader.cpp:
        (WebCore::FrameLoader::endIfNotLoading): Only try an icon load if we're not restoring from the page cache
        (WebCore::FrameLoader::startIconLoader): Added helpful logging that helped me track this down
        (WebCore::FrameLoader::commitIconURLToIconDatabase): Ditto (and fixed a comment typo)

        * loader/icon/IconLoader.cpp:
        (WebCore::IconLoader::stopLoading): Don't null out the ResourceLoader here, as clearLoadingState() does that
        (WebCore::IconLoader::finishLoading): Added helpful logging that helped me track this down



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@21612 268f45cc-cd09-0410-ab3c-d52691b4dbfc