On SIGHUP beakerd reloads its configuration. This support was originally added at a time when beakerd wasn't rotating its own logs, and it didn't shut itself down cleanly (threads were killed in the middle of processing recipes). Now that those reasons no longer apply, we should remove the reload support because it causes a lot of extra complexity, particularly in dealing with logging configuration. See http://gerrit.beaker-project.org/1647 for some discussion.
SIGHUP handling was removed as part of bug 963542, released with Beaker 0.14.