Fixes several bugs in daala-dist, sub8x8 inter mode
with --disable-cb4x4.

Changes on BD-Rate are:
(objective-1-fast, high delay mode, --disalble-cb4x4):

   PSNR | PSNR Cb | PSNR Cr | PSNR HVS |    SSIM | MS SSIM | CIEDE 2000
14.0337 | 13.0132 | 14.6055 |  -3.2030 | -2.2092 | -9.3902 |    10.3399

Additionally, BD-Rate change by daala-dist in enforced MSE mode
which can show the correctness of implementation is

  PSNR | PSNR Cb | PSNR Cr | PSNR HVS |   SSIM | MS SSIM | CIEDE 2000
0.0048 |  0.0789 |  0.0209 |   0.0443 | 0.0137 |  0.0411 |     0.0441

Change-Id: I68ec90c6072aa3564522c2b8e87b62a998cec47c