GitLab CI runner rebuilt

[Andrew Bartlett]

Just a heads up that I've rebuilt the GitLab runner in rackspace.

The runner has been simplified, the (unused) installation of Docker on
the bastian host has been removed, and we have moved to the gitlab
maintained fork of docker-machine.

(I tried to move to rancher-machine, but it fails in the rackspace
driver). 

Finally, I removed password authentication from SSH (which is enabled
by default in the rackspace images, ouch!) on the bastian host, which
should reduce the load from the attackers. 

I'm still hoping to move to OSU-OSL but I think I'm out of time before
Christmas and some of the tools are not working properly for me there.

If you notice anything odd, do let me know.

Andrew Bartlett
-- 
Andrew Bartlett
https://samba.org/~abartlet/
Authentication Developer, Samba Team         https://samba.org
Samba Development and Support, Catalyst IT - Expert Open Source
Solutions
https://catalyst.net.nz/services/samba