Handle or voidify all calls to close_all_fds()

In activate, it is important that we close the fds. In other cases, meh.

src/nspawn/nspawn-setuid.c

@@ -43,7 +43,7 @@ static int spawn_getent(const char *database, const char *key, pid_t *rpid) {
                 if (rearrange_stdio(-1, pipe_fds[1], -1) < 0)
                         _exit(EXIT_FAILURE);
 
-                close_all_fds(NULL, 0);
+                (void) close_all_fds(NULL, 0);
 
                 (void) rlimit_nofile_safe();
 

src/nspawn/nspawn-stub-pid1.c

@@ -67,7 +67,7 @@ int stub_pid1(sd_id128_t uuid) {
         reset_all_signal_handlers();
 
         log_close();
-        close_all_fds(NULL, 0);
+        (void) close_all_fds(NULL, 0);
         log_open();
 
         /* Flush out /proc/self/environ, so that we don't leak the environment from the host into the container. Also,