Also ensure prompt_yes_no always print the message with a trailing space,
which is more pleasing to the eye.
* etc/guix-daemon.conf.in <--discover=no>: New guix-daemon option.
* etc/guix-daemon.service.in: Likewise.
* etc/init.d/guix-daemon.in: Likewise.
* etc/openrc/guix-daemon.in: Likewise.
* etc/guix-install.sh (configure_substitute_discovery): New procedure.
(sys_enable_guix_daemon): Ask the user whether automatic substitute discovery
should be enabled. Set the '--discover' argument accordingly.
(prompt_yes_no): Add a trailing space to the message.
(sys_authorize_build_farms): Remove trailing space from the message argument.
* NEWS (Distribution): Add news.
The 'task' means that events that led to this job starting will be blocked
until it has stopped. Tasks are short lived jobs, whereas the guix-daemon is a
long lived service. Including 'task' means that attempts to start the
guix-daemon appear to hang, as upstart waits for it to exit.
* etc/guix-daemon.conf.in: Remove 'task'.
Otherwise, users will be stuck running an old copy of guix and the guix-daemon
if they copy the service files instead of symlinking them.
* etc/guix-daemon.conf.in, etc/guix-daemon.service.in, etc/guix-publish.conf.in,
etc/guix-publish.service.in: Expand @localstatedir@ instead of @bindir@.
* nix/local.mk (etc/guix-%.service, etc/guix-%.conf): Use @localstatedir@
instead of @bindir@.