CECPQ1: change from named curve to ciphersuite.

This is easier to deploy, and more obvious.  This commit reverts a few
pieces of e25775bc, but keeps most of it.

Change-Id: If8d657a4221c665349c06041bb12fffca1527a2c
Reviewed-on: https://boringssl-review.googlesource.com/8061
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
index 1648922..3770c6e 100644
--- a/include/openssl/ssl.h
+++ b/include/openssl/ssl.h
@@ -1098,6 +1098,9 @@
 /* SSL_CIPHER_is_ECDHE returns one if |cipher| uses ECDHE. */
 OPENSSL_EXPORT int SSL_CIPHER_is_ECDHE(const SSL_CIPHER *cipher);
 
+/* SSL_CIPHER_is_CECPQ1 returns one if |cipher| uses CECPQ1. */
+OPENSSL_EXPORT int SSL_CIPHER_is_CECPQ1(const SSL_CIPHER *cipher);
+
 /* SSL_CIPHER_get_min_version returns the minimum protocol version required
  * for |cipher|. */
 OPENSSL_EXPORT uint16_t SSL_CIPHER_get_min_version(const SSL_CIPHER *cipher);
@@ -3358,6 +3361,7 @@
 #define SSL_TXT_kDHE "kDHE"
 #define SSL_TXT_kEDH "kEDH"
 #define SSL_TXT_kECDHE "kECDHE"
+#define SSL_TXT_kCECPQ1 "kCECPQ1"
 #define SSL_TXT_kEECDH "kEECDH"
 #define SSL_TXT_kPSK "kPSK"
 #define SSL_TXT_aRSA "aRSA"