titlebar: restack clients on titlebar add

This is mandatory since we do not know where the client is on stack.

Signed-off-by: Julien Danjou <julien@danjou.info>

client.c

@@ -1353,6 +1353,7 @@ luaA_client_newindex(lua_State *L)
             titlebar_ref(t);
             titlebar_init(*c);
         }
+        client_stack();
         break;
       default:
         return 0;

titlebar.c

@@ -406,6 +406,7 @@ luaA_titlebar_newindex(lua_State *L)
                 client_need_arrange(c);
             }
         }
+        client_stack();
         break;
       case A_TK_ALIGN:
         if((buf = luaL_checklstring(L, 3, &len)))