Fix pipfile creation with unnamed project

[techalchemy]

Fix pipfile creation with unnamed project

• Fixes PipfileNotFound raised for no Pipfile while installing #3260

[techalchemy]

The new test does fail when run against master in the expected way:

________________________________________________________________________________ test_install_creates_pipfile ________________________________________________________________________________
[gw0] linux -- Python 3.7.1 /home/hawk/.virtualenvs/pipenv-MfOPs1lW/bin/python

PipenvInstance = <class 'tests.integration.conftest._PipenvInstance'>

    @pytest.mark.install
    def test_install_creates_pipfile(PipenvInstance):
        with PipenvInstance(chdir=True) as p:
            if os.path.isfile(p.pipfile_path):
                os.unlink(p.pipfile_path)
            if "PIPENV_PIPFILE" in os.environ:
                del os.environ["PIPENV_PIPFILE"]
            assert not os.path.isfile(p.pipfile_path)
            c = p.pipenv("install")
>           assert c.return_code == 0
E           AssertionError: assert 1 == 0
E            +  where 1 = <Command 'pipenv install'>.return_code

tests/integration/test_install_basic.py:432: AssertionError
------------------------------------------------------------------------------------ Captured stdout call ------------------------------------------------------------------------------------
$ pipenv install

[pipenv.exceptions.PipfileNotFound]:   File "/home/hawk/git/pipenv/pipenv/vendor/click/decorators.py", line 64, in new_func
[pipenv.exceptions.PipfileNotFound]:       return ctx.invoke(f, obj, *args, **kwargs)
[pipenv.exceptions.PipfileNotFound]:   File "/home/hawk/git/pipenv/pipenv/vendor/click/core.py", line 555, in invoke
[pipenv.exceptions.PipfileNotFound]:       return callback(*args, **kwargs)
[pipenv.exceptions.PipfileNotFound]:   File "/home/hawk/git/pipenv/pipenv/vendor/click/decorators.py", line 17, in new_func
[pipenv.exceptions.PipfileNotFound]:       return f(get_current_context(), *args, **kwargs)
[pipenv.exceptions.PipfileNotFound]:   File "/home/hawk/git/pipenv/pipenv/cli/command.py", line 250, in install
[pipenv.exceptions.PipfileNotFound]:       editable_packages=state.installstate.editables,
[pipenv.exceptions.PipfileNotFound]:   File "/home/hawk/git/pipenv/pipenv/core.py", line 1718, in do_install
[pipenv.exceptions.PipfileNotFound]:       raise exceptions.PipfileNotFound(project.path_to("Pipfile"))
ERROR: /tmp/pipenv-8urp4wrr-project/Pipfile not found! Aborting! Please ensure that the file exists and is located in your project root directory.

Command failed...
===Flaky Test Report===

[frostming]

LGTM🍰