Updating a crate that pins a crate that pins a missing crate missing feedback

[mosteo]

Usual setup in which lib is tested via a nested libtest. If lib itself is using a pin to a missing directory, the update will fail.

This must indeed fail, if the pin is not to a repo that can be retrieved, but some better feedback should be provided that there is a broken pin in the solution. For example, if the broken pin is a direct dependeny, we don't allow loading the manifest until that is fixed. Should be the same here.