Follow-up: Remove old ReportedDelay AEC config

This is a follow-up to r9531, where the configuration ReportedDelay
was replaced by DelayAgnostic. The config was kept in the code to
avoid API breakages. In https://codereview.chromium.org/1219263003/
depending code has been updated to avoid breakages.

BUG=webrtc:4651
R=bjornv@webrtc.org

Review URL: https://codereview.webrtc.org/1212653012

Cr-Commit-Position: refs/heads/master@{#9536}
2 files changed