message: [cluster-test] Set timeout for running ssh
  This sets 15 seconds for total ssh execution to prevent spurious failures like 'experiment did not complete on time'
  Closes:
  Approved by: ankushagarwal
diff: @@ -44,13 +44,14 @@ impl Instance {
  {
  let ssh_dest = format!("ec2-user@{}", self.ip);
  let ssh_args = vec![
  + "ssh",
  "-i",
  "/libra_rsa",
  "-oStrictHostKeyChecking=no",
  ssh_dest.as_str(),
  ];
  - let mut ssh_cmd = Command::new("ssh");
  - ssh_cmd.args(ssh_args).args(args);
  + let mut ssh_cmd = Command::new("timeout");
  + ssh_cmd.arg("15").args(ssh_args).args(args);
  if no_std_err {
  ssh_cmd.stderr(Stdio::null());
  }
  