lua close state on os.exit

Change-Id: I376fad0f92f1155698740e1b8599a3385998575c
diff --git a/apps/plugins/lua/loslib.c b/apps/plugins/lua/loslib.c
index 6cb8c05..dce8811 100644
--- a/apps/plugins/lua/loslib.c
+++ b/apps/plugins/lua/loslib.c
@@ -172,7 +172,9 @@
 
 
 static int os_exit (lua_State *L) {
-  exit(luaL_optint(L, 1, EXIT_SUCCESS));
+  int status = luaL_optint(L, 1, EXIT_SUCCESS);
+  lua_close(L);
+  exit(status);
   return EXIT_SUCCESS; /* never reached, surpress warning */
 }