various: remove unnecessary check before sd_event_source_set_enabled()

sd_event_source_set_enabled() does the same check internally.

src/core/automount.c

@@ -734,9 +734,6 @@ static int automount_start_expire(Automount *a) {
 static void automount_stop_expire(Automount *a) {
         assert(a);
 
-        if (!a->expire_event_source)
-                return;
-
         (void) sd_event_source_set_enabled(a->expire_event_source, SD_EVENT_OFF);
 }
 

src/core/socket.c

@@ -1734,9 +1734,6 @@ static void socket_unwatch_fds(Socket *s) {
                 if (p->fd < 0)
                         continue;
 
-                if (!p->event_source)
-                        continue;
-
                 r = sd_event_source_set_enabled(p->event_source, SD_EVENT_OFF);
                 if (r < 0)
                         log_unit_debug_errno(UNIT(s), r, "Failed to disable event source: %m");

src/core/timer.c

@@ -514,7 +514,6 @@ static void timer_enter_waiting(Timer *t, bool time_change) {
                                 goto fail;
                         }
                 } else {
-
                         r = sd_event_add_time(
                                         UNIT(t)->manager->event,
                                         &t->monotonic_event_source,
@@ -529,8 +528,7 @@ static void timer_enter_waiting(Timer *t, bool time_change) {
                         (void) sd_event_source_set_description(t->monotonic_event_source, "timer-monotonic");
                 }
 
-        } else if (t->monotonic_event_source) {
-
+        } else {
                 r = sd_event_source_set_enabled(t->monotonic_event_source, SD_EVENT_OFF);
                 if (r < 0) {
                         log_unit_warning_errno(UNIT(t), r, "Failed to disable monotonic event source: %m");