fix bug for android 2.3.3

Android API 11 :
1. canvas's width and height is larger than the view's width and height.
2. after invoke scroller's flipping. setFinalX with a futher value, after scroller
 end flping, it's jump to the final X.


Signed-off-by: qijiang.guo <qijiang.guo@gmail.com>