message: Added ptrace event for clones
  Missed out originally, added with brand new error message
diff: @@ -310,6 +310,15 @@ impl <'a>LinuxData<'a> {
  fn handle_ptrace_event(&mut self) -> Result<TestState> {
  match self.wait {
  + WaitStatus::PtraceEvent(child, signal::SIGTRAP, PTRACE_EVENT_CLONE) => {
  + if get_event_data(child).is_ok() {
  + continue_exec(child, None)?;
  + Ok(TestState::Waiting{start_time:0})
  + } else {
  + self.error_message = Some("Error occurred upon test executable thread creation".to_string());
  + Ok(TestState::Unrecoverable)
  + }
  + },
  WaitStatus::PtraceEvent(child, signal::SIGTRAP, PTRACE_EVENT_FORK) => {
  continue_exec(child, None)?;
  Ok(TestState::Waiting{start_time:0})
  