Enable TLS 1.3 by default in bssl tool.

Change-Id: I4b586dce37f4db0770e516888c2eeeae3ecffd97
Reviewed-on: https://boringssl-review.googlesource.com/13784
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/tool/client.cc b/tool/client.cc
index 0301a81..8e0ef2d 100644
--- a/tool/client.cc
+++ b/tool/client.cc
@@ -282,16 +282,16 @@
     return false;
   }
 
-  if (args_map.count("-max-version") != 0) {
-    uint16_t version;
-    if (!VersionFromString(&version, args_map["-max-version"])) {
-      fprintf(stderr, "Unknown protocol version: '%s'\n",
-              args_map["-max-version"].c_str());
-      return false;
-    }
-    if (!SSL_CTX_set_max_proto_version(ctx.get(), version)) {
-      return false;
-    }
+  uint16_t max_version = TLS1_3_VERSION;
+  if (args_map.count("-max-version") != 0 &&
+      !VersionFromString(&max_version, args_map["-max-version"])) {
+    fprintf(stderr, "Unknown protocol version: '%s'\n",
+            args_map["-max-version"].c_str());
+    return false;
+  }
+
+  if (!SSL_CTX_set_max_proto_version(ctx.get(), max_version)) {
+    return false;
   }
 
   if (args_map.count("-min-version") != 0) {