Build Agent not working over https

http://jetbrains.net/jira/browse/TW-4520

I seem to be stuck setting up a Build Agent to work over https. It's
being told by the server to update, but it's trying to go to
http://.../buildAgent/update.zip rather than https://... and it's failing.

I have Apache forwarding http to https, and the http url resolves fine
in my browser, but not in the build agent.

The JIRA issue has more details, including a snippet from the build
agent log file.