Pipenv 2018.10.9 fails when trying to install from git subdirectory

[JSchulte01]

Issue description

I recently upgraded to the latest pipenv 2018.10.9 and immediately started getting install failures on pipenv install. Failures only seem to affect git subdirectory commands i.e.
{editable = true, git = "ssh://git@bitbucket.org/<org>/<repo>.git", ref="master", subdirectory="modules/<pkg>/"}

The repo is organised as a namespaced repo of subpackages. i.e modules//

Expected result

Describe what you expected.

Actual result

I dont have a traceback currently because I uninstalled to workaround before reporting. But the general result is it attempts to install from the root directory and fails when it does not find a setup.py.

Steps to replicate

1. Upgrade to pipenv 2018.10.9
2. Run pipenv install, ensuring you use a namespace packaged repo as above.

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[techalchemy]

this version is pretty broken around certain features, can you test against master and let me know if that works?

[JSchulte01]

This error is caused by setuptools: issue #1321