You may not use continue when there's no loop to continue

In /includes/cache/service.php
there's the following:

		if (!file_exists($filename))

		{

			continue;

		}

The problem here is that this code is not inside a loop so it won't work.
I don't know how this part of phpBB3 works so I think I cannot solve this bug.

I'm testing on the current version on git.