FALLBACK_SCSV is an RFC now.

Update references.

Change-Id: I56af31529cf6bfd00d3f0bb9b6281645ed134c5c
Reviewed-on: https://boringssl-review.googlesource.com/5555
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
index bbd80a9..4174594 100644
--- a/include/openssl/ssl.h
+++ b/include/openssl/ssl.h
@@ -448,12 +448,10 @@
 
 /* SSL_MODE_SEND_FALLBACK_SCSV sends TLS_FALLBACK_SCSV in the ClientHello.
  * To be set only by applications that reconnect with a downgraded protocol
- * version; see https://tools.ietf.org/html/draft-ietf-tls-downgrade-scsv-05
- * for details.
+ * version; see RFC 7507 for details.
  *
  * DO NOT ENABLE THIS if your application attempts a normal handshake. Only use
- * this in explicit fallback retries, following the guidance in
- * draft-ietf-tls-downgrade-scsv-05. */
+ * this in explicit fallback retries, following the guidance in RFC 7507. */
 #define SSL_MODE_SEND_FALLBACK_SCSV 0x00000400L
 
 /* The following flags do nothing and are included only to make it easier to