message: Add panic logs in island init process
  When the container is malformed e.g the init binary is not executible
  the runtimes init process shal fail with a message.
diff: @@ -384,7 +384,12 @@ pub(super) fn init(
  // TODO: Move the allocations to parent/parent
  set_seccomp_filter(container.manifest.seccomp.as_ref());
  - panic!("{:?}", unistd::execve(&init, &argv, &env))
  + panic!(
  + "Execve: {:?} {:?}: {:?}",
  + &init,
  + &argv,
  + unistd::execve(&init, &argv, &env)
  + )
  }
  },
  Err(e) => panic!("Clone error: {}", e),
  @@ -397,6 +402,10 @@ pub(super) fn init(
  // TODO: /dev mounts from manifest: full or minimal
  fn mount(mounts: &[Mount]) {
  for mount in mounts {
  + if !mount.target.exists() {
  + panic!("Missing mount point {}", mount.target.display())
  + }
  +
  nix::mount::mount(
  mount.source.as_ref(),
  &mount.target,
  @@ -404,7 +413,7 @@ fn mount(mounts: &[Mount]) {
  mount.flags,
  mount.data.as_deref(),
  )
  - .expect("Failed to mount");
  + .expect(&format!("Failed to mount {:?}", mount));
  }
  }
  