This means we do a bit less string operations, but it also allows us
to pick up the collection-id when listing refs from a file: uri, fixing
the issues described in https://github.com/flatpak/flatpak/pull/3909
This slightly changes the behaviour of collection ids and remotes.
When listing regular remotes we only ever return the refs with the
collection id specified by the configuration of that remote. However,
when specifying a file: uri for the remote name we return all the refs
in the repo, with their corresponding collection id.
This means the test suite has to change a bit as before we returned
all the collrefs from the remote, not just the one matching the configured
collection id.
db11607016
