this resolves problems with aio roots becoming invalid after fork (which
so far forced us to run the daemon loop in an aio-rootless thread), does
not require restarting the signal handler thread in the subdaemon (since
we no longer lose it), and is a step towards solving #18 (with transient
daemons doing the store manipulation started transparently when needed).
Change-Id: Iad0149cbc807e31964407c9a83d12314702c8122
eldritch horrors
7b37d5ea6a