message: openssl_adapter: document SSL_CTX_set_verify_depth behaviour
  document the reason for the depth setting in the code.
  Cr-Commit-Position: refs/heads/master@{#34336}
diff: @@ -981,6 +981,9 @@ SSL_CTX* OpenSSLAdapter::CreateContext(SSLMode mode, bool enable_cache) {
  SSL_CTX_set_custom_verify(ctx, SSL_VERIFY_PEER, SSLVerifyCallback);
  #else
  SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, SSLVerifyCallback);
  + // Verify certificate chains up to a depth of 4. This is not
  + // needed for DTLS-SRTP which uses self-signed certificates
  + // (so the depth is 0) but is required to support TURN/TLS.
  SSL_CTX_set_verify_depth(ctx, 4);
  #endif
  // Use defaults, but disable HMAC-SHA256 and HMAC-SHA384 ciphers
  