Add a missing case to SSL_error_description.

Change-Id: Ib8aaa2b6bfafc88cf51d2ae0f085bb87275a4306
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/47585
Reviewed-by: Adam Langley <agl@google.com>

ssl/ssl_lib.cc

diff --git a/ssl/ssl_lib.cc b/ssl/ssl_lib.cc
index 97eeb12..5b06005 100644
--- a/ssl/ssl_lib.cc
+++ b/ssl/ssl_lib.cc
@@ -1461,6 +1461,8 @@
       return "HANDOFF";
     case SSL_ERROR_HANDBACK:
       return "HANDBACK";
+    case SSL_ERROR_WANT_RENEGOTIATE:
+      return "WANT_RENEGOTIATE";
     case SSL_ERROR_HANDSHAKE_HINTS_READY:
       return "HANDSHAKE_HINTS_READY";
     default: