ini configuration are not found in subdirectories when specifying tests with ::

When a pytest.ini exists in a subdirectory (i.e. `subdir/pytest.ini`), it gets picked parsed and used when invoking pytest with `pytest subdir` rather than using a `pytest.ini` in the root directory.

However, when specifying a test with double colons (`::`) on the command line like `pytest subdir/test_foo.py::test_foo` the `subdir/pytest.ini` configuration files is not used.