Use scopers in tool/

Change-Id: I4e61dc57d1ec65e892b1933f35663db164f017eb
Reviewed-on: https://boringssl-review.googlesource.com/11681
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/tool/transport_common.cc b/tool/transport_common.cc
index d5326b5..8761fea 100644
--- a/tool/transport_common.cc
+++ b/tool/transport_common.cc
@@ -268,16 +268,15 @@
   fprintf(stderr, "  ALPN protocol: %.*s\n", alpn_len, alpn);
 
   // Print the server cert subject and issuer names.
-  X509 *peer = SSL_get_peer_certificate(ssl);
-  if (peer != NULL) {
+  bssl::UniquePtr<X509> peer(SSL_get_peer_certificate(ssl));
+  if (peer != nullptr) {
     fprintf(stderr, "  Cert subject: ");
-    X509_NAME_print_ex_fp(stderr, X509_get_subject_name(peer), 0,
+    X509_NAME_print_ex_fp(stderr, X509_get_subject_name(peer.get()), 0,
                           XN_FLAG_ONELINE);
     fprintf(stderr, "\n  Cert issuer: ");
-    X509_NAME_print_ex_fp(stderr, X509_get_issuer_name(peer), 0,
+    X509_NAME_print_ex_fp(stderr, X509_get_issuer_name(peer.get()), 0,
                           XN_FLAG_ONELINE);
     fprintf(stderr, "\n");
-    X509_free(peer);
   }
 }