(ScrollView) If animation duration is 0, then return final position in completed...

(ScrollView) If animation duration is 0, then return final position in completed signal

[problem]     If the animation duration is 0, we still return the current scroll position. This is
              wrong as in the next frame, we will be at the requested position.
[cause]       N/A
[solution]    If we do not kick off an animation, then we should check whether the duration was 0.
              If it was, we should return the target-position instead.

Change-Id: I3e1a96b3de7ca2685a16f6dd6b8ce5aebc1c78af
Signed-off-by: Adeel Kazmi <adeel.kazmi@samsung.com>