cleanup temporary directory when restarting and not using XDG_RUNTIME_DIR

fixes #1253

src/commands.c

@@ -1682,6 +1682,14 @@ void cmd_reload(I3_CMD) {
  */
 void cmd_restart(I3_CMD) {
     LOG("restarting i3\n");
+    ipc_shutdown();
+    /* We need to call this manually since atexit handlers don’t get called
+     * when exec()ing */
+    purge_zerobyte_logfile();
+    /* The unlink call is intentionally after the purge_zerobyte_logfile() so
+     * that the latter does not remove the directory yet. We need to store the
+     * restart layout state in there. */
+    unlink(config.ipc_socket_path);
     i3_restart(false);
 
     // XXX: default reply for now, make this a better reply