SSL_set_read_ahead no longer needed with BoringSSL.

In https://boringssl-review.googlesource.com/#/c/4820/ BoringSSL
deprecated "SSL_set_read_ahead". That commit has rolled into
Chromium/WebRTC, so calling the function is no longer needed.

BUG=chromium:447431
R=juberti@google.com

Review URL: https://webrtc-codereview.appspot.com/55559004

Cr-Commit-Position: refs/heads/master@{#9355}
1 file changed