networkd: remove vestigial event sources

187fe1db took advantage of floating events, but didn't remove pointers
it made superfluous.

src/network/networkd-manager.c

@@ -146,8 +146,6 @@ void manager_free(Manager *m) {
         udev_unref(m->udev);
         sd_bus_unref(m->bus);
         sd_event_source_unref(m->udev_event_source);
-        sd_event_source_unref(m->sigterm_event_source);
-        sd_event_source_unref(m->sigint_event_source);
         sd_event_unref(m->event);
 
         while ((link = hashmap_first(m->links)))

src/network/networkd.h

@@ -174,8 +174,6 @@ struct Manager {
         struct udev *udev;
         struct udev_monitor *udev_monitor;
         sd_event_source *udev_event_source;
-        sd_event_source *sigterm_event_source;
-        sd_event_source *sigint_event_source;
 
         char *state_file;