The bug was introduced here:
https://chromium-review.googlesource.com/#/c/399975/4/av1/encoder/bitstream.c
In that patch, I had removed 2nd declaration of a variable of the same
name. But it turns out that the two variables actually had a different
type (even though the name was same).

Now, we keep both variables, but rename one of them -- that fixes the
mismatch. While we are at it, made both variables local as well.

The fix can be verified as follows:
../../libvpx/configure --enable-experimental --enable-supertx
--enable-var-tx --enable-entropy --enable-internal-stats && make clean
&& make -j16

aomenc -o soccer_cif_1000_av1_b8.webm ../soccer_cif.y4m --codec=av1
--limit=50 --skip=0 -p 2 --pass=1 --fpf=soccer_cif_av1.fpf --good
--cpu-used=0 --target-bitrate=1000 --lag-in-frames=25 --min-q=0
--max-q=63 --auto-alt-ref=1 --kf-max-dist=150 --kf-min-dist=0
--drop-frame=0 --static-thresh=0 --bias-pct=50 --minsection-pct=0
--maxsection-pct=2000 --arnr-maxframes=7 --arnr-strength=5 --sharpness=0
--undershoot-pct=100 --overshoot-pct=100 --frame-parallel=0
--tile-columns=0 --profile=0 --test-decode=warn

aomenc -o soccer_cif_1000_av1_b8.webm ../soccer_cif.y4m --codec=av1
--limit=50 --skip=0 -p 2 --pass=2 --fpf=soccer_cif_av1.fpf --good
--cpu-used=0 --target-bitrate=1000 --lag-in-frames=25 --min-q=0
--max-q=63 --auto-alt-ref=1 --kf-max-dist=150 --kf-min-dist=0
--drop-frame=0 --static-thresh=0 --bias-pct=50 --minsection-pct=0
--maxsection-pct=2000 --arnr-maxframes=7 --arnr-strength=5 --sharpness=0
--undershoot-pct=100 --overshoot-pct=100 --frame-parallel=0
--tile-columns=0 --profile=0 --test-decode=warn -v --psnr

Change-Id: Ibd72dbe1f620e6de231513220ee4e190606613ae