Revert "Skip the last frame update for some frame repeats."

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 e5112b3ae3352c4c55fb31235305f3f80f4b8f7e.

Change-Id: I315c5200414de89458015823344b7367e9dd75ba