This patch changes the Entries::in_collection() interface to return a
Result<()>. This is needed because the fs backend implementation should
be able to check whether a directory actually exists whenever we change
the iterator.
If the implementation detects that the directory does not exist, we can
fail early and error out.
All usages of the interface are adapted by the patch as well.
Signed-off-by: Matthias Beyer <mail@beyermatthias.de>
Matthias Beyer
5c8af4460e