Fix bug in ramp-up tests stats where rtx was accounted for in the media ssrc.

Fix bug in ramp-up tests stats where rtx was accounted for in the media ssrc.

BUG=chromium:536941
Committed: https://crrev.com/092508a5c52d0d57cad8ac423187e64237e61e53
Cr-Commit-Position: refs/heads/master@{#10104}

[stefan-webrtc, 2015-09-29 07:28:41]

stefan@webrtc.org changed reviewers:
+ pbos@webrtc.org

[stefan-webrtc, 2015-09-29 07:28:45]

The CQ bit was checked by stefan@webrtc.org

[commit-bot: I haz the power, 2015-09-29 07:28:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1380483002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1380483002/1

[commit-bot: I haz the power, 2015-09-29 07:28:57]

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

[commit-bot: I haz the power, 2015-09-29 07:28:58]

No L-G-T-M from a valid reviewer yet. Only full committers are accepted.
Even if an L-G-T-M may have been provided, it was from a non-committer,
_not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[stefan-webrtc, 2015-09-29 07:38:27]

The CQ bit was checked by stefan@webrtc.org to run a CQ dry run

[commit-bot: I haz the power, 2015-09-29 07:38:33]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1380483002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1380483002/1

[pbos-webrtc, 2015-09-29 08:46:00]

lgtm, thanks

[commit-bot: I haz the power, 2015-09-29 09:20:07]

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

[commit-bot: I haz the power, 2015-09-29 09:20:07]

Dry run: This issue passed the CQ dry run.

[stefan-webrtc, 2015-09-29 09:25:19]

The CQ bit was checked by stefan@webrtc.org

[commit-bot: I haz the power, 2015-09-29 09:25:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1380483002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1380483002/1

[commit-bot: I haz the power, 2015-09-29 09:26:47]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-29 09:27:01]

Patchset 1 (id:??) landed as
https://crrev.com/092508a5c52d0d57cad8ac423187e64237e61e53
Cr-Commit-Position: refs/heads/master@{#10104}