Revert "Skip the last frame update for some frame repeats."
Testing on another rate control patch reveals that in some situations, where the encoder is flipping in and out of arf mode, we get an encoder decoder mismatch. Whilst it is still not clear why, skipping the last buffer update seems to trigger the problem. Until I can establish why, or if there is another underlying cause, I am reverting this change. This reverts commit e5112b3a. Change-Id: I315c5200414de89458015823344b7367e9dd75ba