Increase the size of the stack buffer to prevent an overflow.

Reviewed-by: NRich Salz <rsalz@openssl.org>
Reviewed-by: NAndy Polyakov <appro@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2721)

crypto/ec/eck_prn.c

@@ -238,7 +238,7 @@ static int print_bin(BIO *fp, const char *name, const unsigned char *buf,
                      size_t len, int off)
 {
     size_t i;
-    char str[128];
+    char str[128 + 1 + 4];
 
     if (buf == NULL)
         return 1;