NetEq: Minor follow-up fix in StatisticsCalculator

NetEq: Minor follow-up fix in StatisticsCalculator

This change follows the recommendation of a post-commit comment in
r9778:
https://codereview.webrtc.org/1296633002/diff/100001/webrtc/modules/audio_coding/neteq/statistics_calculator.cc#newcode198

TBR=pkasting@chromium.org

Committed: https://crrev.com/1e346b20c430bbfab650db6524e39721851bcf2e
Cr-Commit-Position: refs/heads/master@{#9803}

[hlundin-webrtc, 2015-08-27 11:52:46]

The CQ bit was checked by henrik.lundin@webrtc.org

[commit-bot: I haz the power, 2015-08-27 11:52:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1319953002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1319953002/1

[commit-bot: I haz the power, 2015-08-27 13:53:16]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-08-27 13:53:16]

Try jobs failed on following builders:
  android on tryserver.webrtc (JOB_TIMED_OUT, no build URL)
  android_rel on tryserver.webrtc (JOB_TIMED_OUT, no build URL)
  win_baremetal on tryserver.webrtc (JOB_TIMED_OUT, no build URL)

[Peter Kasting, 2015-08-27 18:54:32]

LGTM!

[hlundin-webrtc, 2015-08-27 20:12:56]

The CQ bit was checked by henrik.lundin@webrtc.org

[commit-bot: I haz the power, 2015-08-27 20:13:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1319953002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1319953002/1

[commit-bot: I haz the power, 2015-08-27 20:41:07]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-27 20:41:19]

Patchset 1 (id:??) landed as
https://crrev.com/1e346b20c430bbfab650db6524e39721851bcf2e
Cr-Commit-Position: refs/heads/master@{#9803}