[DGD] Kernel Library: Callouts are back as a resource

[Shentino]

Just as a side note.

Those upgrading to the current version of the kernel library need not remove
callouts as a resource.  Those who have already removed them and wish to
reinstate them will need to audit their mud and reconcile the totals
manually.

This note supersedes the upgrade instructions currently provided, which have
recently been amended.