The header extensions for a receive stream should also be used
for the associated RTX stream, but not for the (RTCP) send stream.
Bug: webrtc:10113
Change-Id: Ibeb25a4490d7f628f1b360bf4d6f7edf444ba22a
Reviewed-on: https://webrtc-review.googlesource.com/c/113807
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Björn Terelius <terelius@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25955}