tree-wide: make sure to flush/close all bus connections when our daemons exit

Let's make sure everything is written out ebfore we exit, so that no
messages keep our bus connections referenced.

Fixes: #11462

src/login/logind.c

@@ -146,7 +146,7 @@ static Manager* manager_unref(Manager *m) {
 
         bus_verify_polkit_async_registry_free(m->polkit_registry);
 
-        sd_bus_unref(m->bus);
+        sd_bus_flush_close_unref(m->bus);
         sd_event_unref(m->event);
 
         safe_close(m->reserve_vt_fd);

src/login/user-runtime-dir.c

@@ -22,7 +22,7 @@
 
 static int acquire_runtime_dir_size(uint64_t *ret) {
         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
-        _cleanup_(sd_bus_unrefp) sd_bus *bus = NULL;
+        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
         int r;
 
         r = sd_bus_default_system(&bus);

src/machine/machined.c

@@ -81,7 +81,7 @@ static Manager* manager_unref(Manager *m) {
 
         bus_verify_polkit_async_registry_free(m->polkit_registry);
 
-        sd_bus_unref(m->bus);
+        sd_bus_flush_close_unref(m->bus);
         sd_event_unref(m->event);
 
         return mfree(m);

src/network/networkd-manager.c

@@ -1456,7 +1456,7 @@ void manager_free(Manager *m) {
 
         sd_device_monitor_unref(m->device_monitor);
 
-        sd_bus_unref(m->bus);
+        sd_bus_flush_close_unref(m->bus);
 
         free(m->dynamic_timezone);
         free(m->dynamic_hostname);

src/portable/portabled.c

@@ -53,7 +53,7 @@ static Manager* manager_unref(Manager *m) {
 
         bus_verify_polkit_async_registry_free(m->polkit_registry);
 
-        sd_bus_unref(m->bus);
+        sd_bus_flush_close_unref(m->bus);
         sd_event_unref(m->event);
 
         return mfree(m);

src/resolve/resolved-manager.c

@@ -689,7 +689,7 @@ Manager *manager_free(Manager *m) {
         manager_mdns_stop(m);
         manager_dns_stub_stop(m);
 
-        sd_bus_unref(m->bus);
+        sd_bus_flush_close_unref(m->bus);
 
         sd_event_source_unref(m->sigusr1_event_source);
         sd_event_source_unref(m->sigusr2_event_source);

src/stdio-bridge/stdio-bridge.c

@@ -91,7 +91,7 @@ static int parse_argv(int argc, char *argv[]) {
 }
 
 static int run(int argc, char *argv[]) {
-        _cleanup_(sd_bus_unrefp) sd_bus *a = NULL, *b = NULL;
+        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *a = NULL, *b = NULL;
         sd_id128_t server_id;
         bool is_unix;
         int r, in_fd, out_fd;

src/timesync/timesyncd-manager.c

@@ -937,7 +937,7 @@ void manager_free(Manager *m) {
         sd_resolve_unref(m->resolve);
         sd_event_unref(m->event);
 
-        sd_bus_unref(m->bus);
+        sd_bus_flush_close_unref(m->bus);
 
         free(m);
 }