Build fix: use of uninitialized variable in ScrollingStateTree
https://bugs.webkit.org/show_bug.cgi?id=114443

Patch by Adenilson Cavalcanti <cavalcantii@gmail.com> on 2013-04-11
Reviewed by Anders Carlsson.

Initialize pointer to zero before use, fixes build.
No new tests, no changes on behavior.

* page/scrolling/ScrollingStateTree.cpp:
(WebCore::ScrollingStateTree::attachNode):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148206 268f45cc-cd09-0410-ab3c-d52691b4dbfc