Stuck on Error page after faulty plugin

I’m getting the following error:

Fatal error: Call to a member function getPriority() on a non-object in /public_html/piwik/core/Notification/Manager.php on line 79

I clicked the PHP Sec Info plugin (even though it said it was broken) and now I ended up with the error.
The error is only shown to admin users, but it prevents you from doing anything.

On the screen it tells you to remove the plugin, but none of the pages work because of the error.

I already removed the plugin folder and set the piwik_option field to autoload 0. Still the same error.

Any suggestions?

Edit: Somehow the problem solved it self. I have no idea how.