Arvados

Near the bottom of the compute node install guide, there's a shell script that includes a Python script to create the initial compute node record in Arvados. This script needs the following improvements:

• socket.gethostname() may return the shortname or FQDN depending on exactly how /etc/hosts is written, which we don't want to fix. Improvement: make sure to always get the FQDN, then split it up into shortname and domain parts.
• The body of the create request should include the address and domain fields.
• The shell should should $ARVADOS_API_HOST in URLs, rather than the api shortname, to work in a wider variety of installations.