Explicitly set ssh to insecure private key.  It is default but sometimes...

There are a number of people having problems accessing the guest machine that vagrant creates.  The message indicates that Permission denied (publickey).  The solution is to explicitly set:

config.ssh.insert_key = true

Now it comes up correctly.  Of course if the installation choses to change to a secure public keys, they can change the Vagrantfile locally or in their own fork to reflect that change.