Fix segfault when no_cookies=true
Fix segfault when no_cookies=true

--- a/doh-client/client.go
+++ b/doh-client/client.go
@@ -114,7 +114,10 @@
 		if err != nil {
 			return nil, err
 		}
-	}
+	} else {
+		c.cookieJar = nil;
+	}
+
 	c.httpClientMux = new(sync.RWMutex)
 	err = c.newHTTPClient()
 	if err != nil {