Clean up CSSPrimitiveValue::equals a bit
https://bugs.webkit.org/show_bug.cgi?id=119195

Reviewed by Andreas Kling.

* css/CSSPrimitiveValue.cpp:
(WebCore::CSSPrimitiveValue::equals):
This should not change behavior, but is quite a bit clearer.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@153412 268f45cc-cd09-0410-ab3c-d52691b4dbfc