Rescale arf bit budget calculation
Rescale arf bit budget calculation

To compute the total budget for a depth layer, exclude the count of
frames that have been allocated the bit budget. This improves the
avg PSNR by 0.15% and overall PSNR by 0.25% for lowres and midres
test sets.

Change-Id: I5115e33e1422dc930179142cd29aeebe97425283

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