Disable transport sequence numbers for audio.

Since this isn't fully wired up yet it shouldn't be part of the
SendSideBwe experiment yet.

BUG=webrtc:5263
R=pbos@webrtc.org

Review URL: https://codereview.webrtc.org/1523283002 .

Cr-Commit-Position: refs/heads/master@{#11029}
diff --git a/talk/media/webrtc/webrtcvoiceengine.cc b/talk/media/webrtc/webrtcvoiceengine.cc
index 2634a24..9eee2af 100644
--- a/talk/media/webrtc/webrtcvoiceengine.cc
+++ b/talk/media/webrtc/webrtcvoiceengine.cc
@@ -930,11 +930,6 @@
   capabilities.header_extensions.push_back(
       RtpHeaderExtension(kRtpAbsoluteSenderTimeHeaderExtension,
                          kRtpAbsoluteSenderTimeHeaderExtensionDefaultId));
-  if (webrtc::field_trial::FindFullName("WebRTC-SendSideBwe") == "Enabled") {
-    capabilities.header_extensions.push_back(RtpHeaderExtension(
-        kRtpTransportSequenceNumberHeaderExtension,
-        kRtpTransportSequenceNumberHeaderExtensionDefaultId));
-  }
   return capabilities;
 }