Always log SDP for WebRTC tests.

Always log SDP for WebRTC tests.

We removed SDP logging earlier because it was bloating bot logs, but
nowadays logs only get printed for failing tests, and SDP information
is very useful to debug for instance webrtc:4570.

BUG=webrtc:4570, 484826, 479093
Committed: https://crrev.com/8fd5dec944a738dc67f514130a94a6837ba33c5b
Cr-Commit-Position: refs/heads/master@{#330722}

[phoglund_chromium, 2015-05-12 11:42:58]

phoglund@chromium.org changed reviewers:
+ kjellander@chromium.org

[kjellander_chromium, 2015-05-12 12:40:04]

lgtm

[phoglund_chromium, 2015-05-20 09:25:24]

The CQ bit was checked by phoglund@chromium.org

[phoglund_chromium, 2015-05-20 09:25:24]

The patchset sent to the CQ was uploaded after l-g-t-m from
kjellander@chromium.org
Link to the patchset: https://codereview.chromium.org/1124323005/#ps60001
(title: "Rebase")

[commit-bot: I haz the power, 2015-05-20 09:25:52]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1124323005/60001

[commit-bot: I haz the power, 2015-05-20 10:38:56]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-05-20 10:39:47]

Patchset 4 (id:??) landed as
https://crrev.com/8fd5dec944a738dc67f514130a94a6837ba33c5b
Cr-Commit-Position: refs/heads/master@{#330722}