ssl/ssl_txt: fix NULL-check

NULL-check for cipher is redundant, instead check if cipher->name is NULL

While here fix formatting of BIO_printf calls as suggested by Andy Polyakov.

CLA: trivial
Reviewed-by: NAndy Polyakov <appro@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6282)

ssl/ssl_txt.c

@@ -44,18 +44,18 @@ int SSL_SESSION_print(BIO *bp, const SSL_SESSION *x)
 
     if (x->cipher == NULL) {
         if (((x->cipher_id) & 0xff000000) == 0x02000000) {
-            if (BIO_printf
-                (bp, "    Cipher    : %06lX\n", x->cipher_id & 0xffffff) <= 0)
+            if (BIO_printf(bp, "    Cipher    : %06lX\n",
+                           x->cipher_id & 0xffffff) <= 0)
                 goto err;
         } else {
-            if (BIO_printf
-                (bp, "    Cipher    : %04lX\n", x->cipher_id & 0xffff) <= 0)
+            if (BIO_printf(bp, "    Cipher    : %04lX\n",
+                           x->cipher_id & 0xffff) <= 0)
                 goto err;
         }
     } else {
-        if (BIO_printf
-            (bp, "    Cipher    : %s\n",
-             ((x->cipher == NULL) ? "unknown" : x->cipher->name)) <= 0)
+        if (BIO_printf(bp, "    Cipher    : %s\n",
+                       ((x->cipher->name == NULL) ? "unknown"
+                                                  : x->cipher->name)) <= 0)
             goto err;
     }
     if (BIO_puts(bp, "    Session-ID: ") <= 0)