fleet template: add || true to some things that could normally fail

Running Docker with --rm and an ExecStop docker rm will cause false failures
of images. This has caused problems when I have been deploying a test
application to my instance of Panamax. This fixes the problem by adding `||
true` to commands that *could* normally return a non-0 exit code so that the
web UI and other parts of Panamax do not get confused.