Change NetEq::InsertPacket to take an RTPHeader

It used to take a WebRtcRTPHeader as input, which has an RTPHeader as
a member. None of the other member in WebRtcRTPHeader where used in
NetEq.

This CL adapts the production code; tests and tools will be converted
in a follow-up CL.

BUG=webrtc:7467

Review-Url: https://codereview.webrtc.org/2807273004
Cr-Commit-Position: refs/heads/master@{#17652}
diff --git a/webrtc/modules/audio_coding/acm2/acm_receiver.cc b/webrtc/modules/audio_coding/acm2/acm_receiver.cc
index 2438bc8..f6f1786 100644
--- a/webrtc/modules/audio_coding/acm2/acm_receiver.cc
+++ b/webrtc/modules/audio_coding/acm2/acm_receiver.cc
@@ -104,8 +104,8 @@
     }
   }  // |crit_sect_| is released.
 
-  if (neteq_->InsertPacket(rtp_header, incoming_payload, receive_timestamp) <
-      0) {
+  if (neteq_->InsertPacket(rtp_header.header, incoming_payload,
+                           receive_timestamp) < 0) {
     LOG(LERROR) << "AcmReceiver::InsertPacket "
                 << static_cast<int>(header->payloadType)
                 << " Failed to insert packet";