Disable all PSK if no callback.

Reviewed-by: Matt Caswell <matt@openssl.org>

ssl/s3_lib.c

diff --git a/ssl/s3_lib.c b/ssl/s3_lib.c
index 8b7c52a..6046580 100644
--- a/ssl/s3_lib.c
+++ b/ssl/s3_lib.c
@@ -3933,7 +3933,7 @@
 
 #ifndef OPENSSL_NO_PSK
         /* with PSK there must be server callback set */
-        if ((alg_k & SSL_kPSK) && s->psk_server_callback == NULL)
+        if ((alg_k & SSL_PSK) && s->psk_server_callback == NULL)
             continue;
 #endif                          /* OPENSSL_NO_PSK */