The upgrade to libsrtp 2.1.0 rolled in https://codereview.webrtc.org/2968463002 so the compatibility code can be removed. BUG=webrtc:7856 Review-Url: https://codereview.webrtc.org/2969543002 Cr-Commit-Position: refs/heads/master@{#19174}
BUG=None Review-Url: https://codereview.webrtc.org/2976443002 Cr-Commit-Position: refs/heads/master@{#18935}