Elementary els_scroller: Fixed bar-dragging.

Elementary els_scroller: Fixed bar-dragging.
[patch] els_scroller - simple bug fix about bar-dragging. by Jae Hwan Kim.

More info:
You can test it in "Scroller" menu of the "elementary_test".
We cannot move the scroller by dragging the bar.
The reason is why the bar-dragging-event and mouse-move-event confict.
When bar is draged, the movement by mouse-move should be freezed.

git-svn-id: svn+ssh://svn.enlightenment.org/var/svn/e/trunk/elementary@57184 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33