Pipenv: Strange always-true if-statement

[thundergolfer]

Issue description

I was investigating some weird action-at-a-distance problem where deleting everything in ~/.local/shared/virtualenvs changed the output of:

python3.6 -m venv .venv
source .venv/bin/activate
pip install pipenv

PIPENV_PIPFILE=~/path/to/my/Pipfile pipenv sync
pipenv run pipdeptree

(Quite weird! But not the concern of this issue)

When I ran into this bit of pipenv source code

https://github.com/pypa/pipenv/blob/1b865647a1ae09957ba414ccbd7b055a65482749/pipenv/utils.py#L1382

That's always going to be True, so it's doing nothing. Also Returns the path of a Pipfile in the docstring should be Returns the path of a requirements.txt file.

Easy things to clean up 🙂

[frostming]

Thanks for that, would you like to shoot a PR for this?

[frostming]

Closed via #3684