list: cannot list content of the data folder

[gurobokum]

Description

dvc list url target where target is out-directory cannot list content of it

Steps for reproduce

$ mkdir folder
$ echo content > folder/data.raw
$ dvc add folder
...
To track the changes with git, run:

        git add folder.dvc .gitignore

$ git add folder.dvc 
$ git commit -m 'add folder'
[master 9dc66b6] add folder
 1 file changed, 7 insertions(+)
 create mode 100644 folder.dvc

$ dvc list . folder
folder
$ dvc list . folder -R
folder

but expects

$ dvc list . folder
data.raw
$ dvc list . folder -R
data.raw

Info

$ dvc --version
0.86.2+d4b019.mod

Relates

#2509

[efiop]

Related to #3182 , as we will also need to download .dir cache files and parse them for this functionality.

[ps-account]

This will be a very useful change, +1

[efiop]

Closing this in favor of #4107 , since it is newer. I have a WIP PR that should be ready later today.