Changing the weights of the first CRF filter in deringing

The old taps were equivalent to [2 2 3 2 3 2 2], while the new taps are
equivalent to [1 2 3 4 3 2 1].

ntt-short results:
         MEDIUM (%) HIGH (%)
    PSNR -0.072101 -0.218669
 PSNRHVS  0.031113 -0.060644
    SSIM  0.007458 -0.171469
FASTSSIM -0.156346 -0.130445

Change-Id: I699862d6a4246986a0d880df26a57b7a28623ce3

diff --git a/vp10/common/od_dering.c b/vp10/common/od_dering.c
index af89b80..f9bf2c8 100644
--- a/vp10/common/od_dering.c
+++ b/vp10/common/od_dering.c

@@ -136,7 +136,7 @@
   int i;
   int j;
   int k;
-  static const int taps[3] = {3, 2, 2};
+  static const int taps[3] = {3, 2, 1};
   for (i = 0; i < 1 << ln; i++) {
     for (j = 0; j < 1 << ln; j++) {
       int16_t sum;