UNDER_ALLOCATED_HACK for scale that detects odd width and odd height were miscalculated and adjusts scaler for it.
BUG=none
TEST=none
Review URL: https://webrtc-codereview.appspot.com/663007

git-svn-id: http://libyuv.googlecode.com/svn/trunk@290 16f28f9a-4ce2-e073-06de-1de4eb20be90