Rename rtp::Packet to RtpPacket

TBR=

Bug: webrtc:5565
Change-Id: Ib66d5ddf2989188e4a058f9a674a66afb5f35c7a
Reviewed-on: https://webrtc-review.googlesource.com/1226
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Original-Commit-Position: refs/heads/master@{#19836}
Cr-Mirrored-From: https://webrtc.googlesource.com/src
Cr-Mirrored-Commit: 8769e1797e19cd8ca1d05defd64b8795402cbb30
4 files changed