daemon: EINTR from kevent(2) is not a fatal error

Simply resume waiting for events rather than exiting if we took a signal
here.

This at least fixes running programs under daemon(8) in the face of
suspend/resume, which I suspect hits us with a spurious EINTR rather
than a signal anyways.

Reported and tested by: manu
Fixes: 8935a3993219b ("daemon: use kqueue for all events")