Fixed minor WebInspector display issue

Fixed minor WebInspector display issue
Clicking on disabled sections in Styles Sidebar Pane creates new elements.
https://bugs.webkit.org/show_bug.cgi?id=81925

Patch by Vlad Voicu <vladv@rosedu.org> on 2012-03-23
Reviewed by Timothy Hatcher

No new tests should be required.

* inspector/front-end/StylesSidebarPane.js:
(WebInspector.StylePropertiesSection.prototype._handleEmptySpaceClick):
(WebInspector.StylePropertyTreeElement.prototype):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@111849 268f45cc-cd09-0410-ab3c-d52691b4dbfc