BUILD FIX: Don't use adoptCF() with NSDictionary * object

Fixes the following build failure:

    In file included from Source/WebCore/platform/network/mac/ResourceErrorMac.mm:27:
    In file included from Source/WebCore/platform/network/cf/ResourceError.h:31:
    /usr/local/include/wtf/RetainPtr.h:81:13: error: static_assert failed "Don't use adoptCF with Objective-C pointer types, use adoptNS."
                static_assert(!std::is_convertible<T, id>::value, "Don't use adoptCF with Objective-C pointer types, use adoptNS.");
                ^             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    /usr/local/include/wtf/RetainPtr.h:274:16: note: in instantiation of member function 'WTF::RetainPtr<NSDictionary *>::RetainPtr' requested here
            return RetainPtr<T>(AdoptCF, o);
                   ^
    Source/WebCore/platform/network/mac/ResourceErrorMac.mm:214:44: note: in instantiation of function template specialization 'WTF::adoptCF<NSDictionary *>' requested here
            RetainPtr<NSDictionary> userInfo = adoptCF((NSDictionary *) CFErrorCopyUserInfo(error));
                                               ^
    1 error generated.

* platform/network/mac/ResourceErrorMac.mm:
(WebCore::ResourceError::nsError): Switch from adoptCF() to
adoptNS().  This is in USE(CFNETWORK) code, so it's not
exercised on the Mac.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@149789 268f45cc-cd09-0410-ab3c-d52691b4dbfc