How can I remove menu items from “my sites” on a multi-site network?

You need to hook into 'wp_before_admin_bar_render', not 'admin_bar_menu'. According to the documentation an action attached to this hook fires before the admin bar is rendered.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)