update README and kali.json

README.md

@@ -19,7 +19,7 @@ Original Kali repository URLs are kept (cloud-init is configured to preserve the
 
 There are two user accounts:
 
-*  `root` with password `toor`, permitted for SSH
+*  `root` with password `toor`, disabled for SSH
 *  `vagrant` with password `vagrant` 
 
 ## Known issues and requested features

kali.json

 {
     "_comment": "qemu at MacOS doesn't support kvm accelerator, it will use the default accelerator, if no accelerator is defined",
-    "_comment": "qemu at MacOS doesn't come with SDL support, use_default_display must be set to true",
+    "__comment": "qemu at MacOS doesn't come with SDL support, use_default_display must be set to true",
     "builders": [
         {
-	    "use_default_display": "true",
+	    "accelerator": "kvm",
             "boot_command": [
                 "<esc><wait>",
                 "install <wait>",