Change return type of AudioEncoder::SetMaxPlaybackRate to void

Change return type of AudioEncoder::SetMaxPlaybackRate to void

There's no point in returning a status code, since the max playback rate
is only a suggestion that the encoder is free to disregard.

Committed: https://crrev.com/3f5f1c2ad305a665fb2ecd3e31c57d405e19af97
Cr-Commit-Position: refs/heads/master@{#9900}

[kwiberg-webrtc, 2015-09-08 12:17:07]

kwiberg@webrtc.org changed reviewers:
+ henrik.lundin@webrtc.org

[hlundin-webrtc, 2015-09-08 12:43:00]

lgtm

[kwiberg-webrtc, 2015-09-09 06:09:59]

The CQ bit was checked by kwiberg@webrtc.org

[commit-bot: I haz the power, 2015-09-09 06:10:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1332573003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1332573003/1

[commit-bot: I haz the power, 2015-09-09 06:15:37]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-09 06:15:51]

Patchset 1 (id:??) landed as
https://crrev.com/3f5f1c2ad305a665fb2ecd3e31c57d405e19af97
Cr-Commit-Position: refs/heads/master@{#9900}