python-pbr: autopkgtest regression with setuptools >= 65

[Graham Inggs]

python-pbr's autopkgtests fail when tested against setuptools 65.5.0-1 [1].

I've copied what I hope is the relevant part of the log below.

It appears a similar issue was worked around in Debian [2].

[1] https://autopkgtest.ubuntu.com/packages/p/python-pbr/lunar/amd64
[2] https://salsa.debian.org/openstack-team/libs/python-pbr/-/commit/1930458a11609981ec2c4bc5c866655ef9d736a1

======================================================================
FAIL: pbr.tests.test_packaging.TestPEP517Support.test_pep_517_support
pbr.tests.test_packaging.TestPEP517Support.test_pep_517_support
----------------------------------------------------------------------
testtools.testresult.real._StringException: traceback-1: {{{
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/fixtures/fixture.py", line 196, in setUp
    self._setUp()
  File "/tmp/autopkgtest.QtfRcB/build.ihN/src/pbr/tests/test_packaging.py", line 193, in _setUp
    self.useFixture(base.CapturedSubprocess(
  File "/usr/lib/python3/dist-packages/fixtures/fixture.py", line 256, in useFixture
    fixture.setUp()
  File "/tmp/autopkgtest.QtfRcB/build.ihN/src/pbr/tests/base.py", line 182, in setUp
    proc = subprocess.Popen(*self.args, **self.kwargs)
  File "/usr/lib/python3.10/subprocess.py", line 971, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/lib/python3.10/subprocess.py", line 1847, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: '/tmp/tmpahex819y/tmp7zkzekem/bin/python'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/fixtures/fixture.py", line 207, in setUp
    raise SetupError(details)
fixtures.fixture.SetupError: {}
}}}

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/fixtures/fixture.py", line 196, in setUp
    self._setUp()
  File "/tmp/autopkgtest.QtfRcB/build.ihN/src/pbr/tests/test_packaging.py", line 193, in _setUp
    self.useFixture(base.CapturedSubprocess(
  File "/usr/lib/python3/dist-packages/fixtures/fixture.py", line 256, in useFixture
    fixture.setUp()
  File "/tmp/autopkgtest.QtfRcB/build.ihN/src/pbr/tests/base.py", line 182, in setUp
    proc = subprocess.Popen(*self.args, **self.kwargs)
  File "/usr/lib/python3.10/subprocess.py", line 971, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/lib/python3.10/subprocess.py", line 1847, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: '/tmp/tmpahex819y/tmp7zkzekem/bin/python'

======================================================================
FAIL: pbr.tests.test_wsgi.TestWsgiScripts.test_wsgi_script_install
pbr.tests.test_wsgi.TestWsgiScripts.test_wsgi_script_install
----------------------------------------------------------------------
testtools.testresult.real._StringException: Traceback (most recent call last):
  File "/tmp/autopkgtest.QtfRcB/build.ihN/src/pbr/tests/test_wsgi.py", line 55, in test_wsgi_script_install
    self._check_wsgi_install_content(stdout)
  File "/tmp/autopkgtest.QtfRcB/build.ihN/src/pbr/tests/test_wsgi.py", line 133, in _check_wsgi_install_content
    script_txt = open(cmd_filename, 'r').read()
FileNotFoundError: [Errno 2] No such file or directory: '/tmp/tmph7s1be8v/tmpvnmkpciz/bin/pbr_test_wsgi'

----------------------------------------------------------------------
Ran 219 tests in 113.773s

FAILED (failures=2, skipped=23)
======> STESTR TEST SUITE FAILED FOR python3.10: displaying pip3 freeze output...