`swift` is specified both as script and entry point, resulting in broken wheels with pep517 installer

[Michał Górny]

The `swift` executable is specified both as a regular script and an entry point, i.e.:

  [files]
  scripts =
      bin/swift

  [entry_points]
  console_scripts =
      swift = swiftclient.shell:main

As a result, the resulting wheel tries to install the same script twice and this causes installer to fail:

$ python -m installer --destdir /tmp/z dist/python_swiftclient-4.0.0-py3-none-any.whl
Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/usr/lib/python3.11/site-packages/installer/__main__.py", line 85, in <module>
    _main(sys.argv[1:], "python -m installer")
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/installer/__main__.py", line 81, in _main
    installer.install(source, destination, {})
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/installer/_core.py", line 109, in install
    record = destination.write_file(
             ^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/installer/destinations.py", line 203, in write_file
    return self.write_to_fs(
           ^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/installer/destinations.py", line 167, in write_to_fs
    raise FileExistsError(message)
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
FileExistsError: File already exists: /tmp/z/usr/bin/swift