Don't allow invalid SCT lists to be set.

This change causes SSL_CTX_set_signed_cert_timestamp_list to check the
SCT list for shallow validity before allowing it to be set.

Change-Id: Ib8a1fe185224ff02ed4ce53a0109e60d934e96b3
Reviewed-on: https://boringssl-review.googlesource.com/12401
Commit-Queue: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/include/openssl/ssl.h b/include/openssl/ssl.h
index e39fa89..f5b9f9d 100644
--- a/include/openssl/ssl.h
+++ b/include/openssl/ssl.h
@@ -4551,6 +4551,7 @@
 #define SSL_R_NO_SHARED_GROUP 266
 #define SSL_R_PRE_SHARED_KEY_MUST_BE_LAST 267
 #define SSL_R_OLD_SESSION_PRF_HASH_MISMATCH 268
+#define SSL_R_INVALID_SCT_LIST 269
 #define SSL_R_SSLV3_ALERT_CLOSE_NOTIFY 1000
 #define SSL_R_SSLV3_ALERT_UNEXPECTED_MESSAGE 1010
 #define SSL_R_SSLV3_ALERT_BAD_RECORD_MAC 1020