Fix slightly quality drop caused at speed 1.

We would skip the rectangular blocks for sub8x8 partitions because
we would conclude that PARTITION_NONE was better than PARTITION_SPLIT,
however, that conclusion was made before we actually really tested
PARTITION_SPLIT.

Change-Id: I8fa91e59894badc1d8cee3ba8a49e40ae4c4a489

vp9/encoder/vp9_encodeframe.c

@@ -1674,6 +1674,7 @@ static void rd_pick_partition(VP9_COMP *cpi, TOKENEXTRA **tp, int mi_row,
             RDCOST(x->rdmult, x->rddiv, srate, sdist)) {
           srate = r4;
           sdist = d4;
+          larger_is_better = 0;
           *(get_sb_partitioning(x, bsize)) = subsize;
           best_rd = MIN(best_rd, RDCOST(x->rdmult, x->rddiv, r4, d4));
         }