deft update vs relative locators

[cgay]

Using the current Deft as of this PR, I get this when runing deft update in the opendylan repo:

WARNING: Library "../bank/bank-protocol" has multiple .lid files for platform "x86_64-darwin".
  /Users/cgay/dylan/workspaces/opendylan/sources/corba/demos/bank/bank-client/protocol/../bank/bank-protocol.hdp
  /Users/cgay/dylan/workspaces/opendylan/sources/corba/demos/bank/bank-server/protocol/../bank/bank-protocol.hdp
Registry will point to the first one, arbitrarily.
No such file or directory: Can't open /Users/cgay/dylan/workspaces/opendylan/registry/x86_64-darwin/../bank/bank-protocol

What changed?