Revert changing to FQDN for hostnames.

5dd1553cca7f7e62eebce75e1d936fc211b239ec moved to using a FQDN for
host names. This caused bug 1151012, but Russell and I also believe
the change will break the host column on the instances table. I can't
do a plain old git revert for this change because a lot of the code
has moved after this change.

Revert to using just the hostname (no domain), and we'll revisit the
intent of 5dd1553cca7f7e62eebce75e1d936fc211b239ec separately.

Resolves bug 1151012.

Change-Id: I944f46d6eb2a6944a12833ec8de7afa2b18e66e7
Merge "Revert changing to FQDN for hostnames."