systemctl: if we managed to reexec the init system via the bus don't retry via signal

If we managed to reeexec the init system via the bus this allows us to
provide synchronous behaviour to callers. This is all lost if we then
repeat the reexecution via SIGTERM.

https://bugzilla.redhat.com/show_bug.cgi?id=698198

src/systemctl.c

@@ -5038,7 +5038,7 @@ static int reload_with_fallback(DBusConnection *bus) {
 
         if (bus) {
                 /* First, try systemd via D-Bus. */
-                if (daemon_reload(bus, NULL) > 0)
+                if (daemon_reload(bus, NULL) >= 0)
                         return 0;
         }