Get rid of useless forward declaration.
https://bugs.webkit.org/show_bug.cgi?id=112449

Patch by Konrad Piascik <kpiascik@blackberry.com> on 2013-03-15
Reviewed by Stephen Chenney.

No behavioural change

* svg/SVGRectElement.cpp:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@145909 268f45cc-cd09-0410-ab3c-d52691b4dbfc