Fixing a comment on AEC divergence metric.

BUG=
R=henrik.lundin@webrtc.org

Review URL: https://codereview.webrtc.org/2102603002 .

Cr-Original-Commit-Position: refs/heads/master@{#13297}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: e01000b9a48eab52b6f5adca17f704c3d3aa2e92
1 file changed