REGRESSION(r143664, r143681): http/tests/security/feed-urls-from-remote.html fails
https://bugs.webkit.org/show_bug.cgi?id=110554

Reviewed by Ryosuke Niwa.

Will fix http/tests/security/feed-urls-from-remote.html for Mac WK1.

* loader/DocumentLoader.cpp:
(WebCore::DocumentLoader::isLoading):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@143695 268f45cc-cd09-0410-ab3c-d52691b4dbfc