core: fix confusing logging of instantaneous jobs

For instantaneous jobs (e.g. starting of targets, sockets, slices, or
Type=simple services) the log shows the job completion
before starting:

        systemd[1]: Created slice -.slice.
        systemd[1]: Starting -.slice.
        systemd[1]: Created slice System Slice.
        systemd[1]: Starting System Slice.
        systemd[1]: Listening on Journal Audit Socket.
        systemd[1]: Starting Journal Audit Socket.
        systemd[1]: Reached target Timers.
        systemd[1]: Starting Timers.
        ...

The reason is that the job completes before the ->start() method returns
and only then does unit_start() print the "Starting ..." message.
The same thing happens when stopping units.

Rather than fixing the order of the messages, let's just not emit the
Starting/Stopping message at all when the job completes instantaneously.
The job completion message is sufficient in this case.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/core/unit.h b/src/core/unit.h
index 9491ef64f9..e60168267f 100644
--- a/src/core/unit.h
+++ b/src/core/unit.h
@@ -544,6 +544,7 @@ int unit_add_node_link(Unit *u, const char *what, bool wants);
 int unit_coldplug(Unit *u);
 
 void unit_status_printf(Unit *u, const char *status, const char *unit_status_msg_format) _printf_(3, 0);
+void unit_status_emit_starting_stopping_reloading(Unit *u, JobType t);
 
 bool unit_need_daemon_reload(Unit *u);