Don't restart titan-launch on initial install

[eschrock]

Problem

As part of the titan CLI, we run titan-launch with restart=always, because we want it to always be running even if the system or docker host restarts. However, if there are failures during initial installation (such as an invalid ZFS version), we will just loop endlessly retrying something that will never succeed.

Solution

Run titan-server once without restart=always and make sure the server comes up. If so, restart it with restart=always. If this is too awkward, we could also add a special mode to titan-server to have it just do the installation and exit, without actually starting the server.

Alternatives

Watch the titan containers to determine what is actually happening.