If we ended up with no modules (e.g., all usnic devices were
excluded), there was a race condition in that the connectivity agent
could tear down its local socket before one or more of the local
clients saw it. Therefore, the local clients would timeout waiting
for the socket to appear.
So move the connectivity checker init later in the bootstrapping
process (it *must* be setup before module_init()), and have it only
invoked if we actually ended up with one or more modules.
afec1454f5