service: pass via FAILED/DEAD before going to AUTO_RESTART

With misconfigured mysql, which uses Restart=always, the following two
messages would loop indefinitely and the "systemctl start" would never
finish:
  Job pending for unit, delaying automatic restart.
  mysqld.service holdoff time over, scheduling restart.

In service_enter_dead() always set the state to SERVICE_FAILED/DEAD first
before setting SERVICE_AUTO_RESTART. This is to allow running jobs to
complete. OnFailure will be also triggered at this point, so there's no
need to do it again from service_stop() (where it was added in commit
f0c7b229).

Note that OnFailure units should better trigger only after giving up
auto-restarting, but that's for another patch to solve.

https://bugzilla.redhat.com/show_bug.cgi?id=832039

src/core/service.c

@@ -1888,6 +1888,8 @@ static void service_enter_dead(Service *s, ServiceResult f, bool allow_restart)
         if (f != SERVICE_SUCCESS)
                 s->result = f;
 
+        service_set_state(s, s->result != SERVICE_SUCCESS ? SERVICE_FAILED : SERVICE_DEAD);
+
         if (allow_restart &&
             !s->forbid_restart &&
             (s->restart == SERVICE_RESTART_ALWAYS ||
@@ -1901,8 +1903,7 @@ static void service_enter_dead(Service *s, ServiceResult f, bool allow_restart)
                         goto fail;
 
                 service_set_state(s, SERVICE_AUTO_RESTART);
-        } else
-                service_set_state(s, s->result != SERVICE_SUCCESS ? SERVICE_FAILED : SERVICE_DEAD);
+        }
 
         s->forbid_restart = false;
 
@@ -2509,7 +2510,7 @@ static int service_stop(Unit *u) {
 
         /* A restart will be scheduled or is in progress. */
         if (s->state == SERVICE_AUTO_RESTART) {
-                service_enter_dead(s, SERVICE_SUCCESS, false);
+                service_set_state(s, SERVICE_DEAD);
                 return 0;
         }