Coverage seems to use stderr on 3.x causing tests to fail

[snowch]

For now the stderr checks have been disabled on 3.x

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FAIL: test_get_output_with_invalid_catalog_id (library.catalog_test.TestCLIGet)
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Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.5.9/x64/lib/python3.5/site-packages/mock/mock.py", line 1330, in patched
    return func(*args, **keywargs)
  File "/home/runner/work/hpecp-python-library/hpecp-python-library/tests/library/catalog_test.py", line 703, in test_get_output_with_invalid_catalog_id
    self.assertEqual(error, expected_stderr)
AssertionError: '/home/runner/work/hpecp-python-library/h[211 chars]ist.' != "'/api/v1/catalog/101' does not exist."
- /home/runner/work/hpecp-python-library/hpecp-python-library/hpecp/client.py:147: ResourceWarning: unclosed file <_io.BufferedReader name='/tmp/tmpo6x_o8sm'>
-   config.readfp(codecs.open(config_file, "r", "utf8"))
  '/api/v1/catalog/101' does not exist.

======================================================================
FAIL: test_get_output_with_unknown_exception (library.catalog_test.TestCLIGet)
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Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.5.9/x64/lib/python3.5/site-packages/mock/mock.py", line 1330, in patched
    return func(*args, **keywargs)
  File "/home/runner/work/hpecp-python-library/hpecp-python-library/tests/library/catalog_test.py", line 731, in test_get_output_with_unknown_exception
    self.assertEqual(stderr, expected_stderr)
AssertionError: '/home/runner/work/hpecp-python-library/hp[227 chars]EBUG' != 'Unknown error. To debug run with env var LOG_LEVEL=DEBUG'
- /home/runner/work/hpecp-python-library/hpecp-python-library/hpecp/client.py:147: ResourceWarning: unclosed file <_io.BufferedReader name='/tmp/tmpc5sx8bhc'>
-   config.readfp(codecs.open(config_file, "r", "utf8"))
  Unknown error. To debug run with env var LOG_LEVEL=DEBUG

======================================================================
FAIL: test_get_failed_login (library.cli_test.TestCLIHttpClient)
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Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.5.9/x64/lib/python3.5/site-packages/mock/mock.py", line 1330, in patched
    return func(*args, **keywargs)
  File "/home/runner/work/hpecp-python-library/hpecp-python-library/tests/library/cli_test.py", line 244, in test_get_failed_login
    "Could not connect to controller - set LOG_LEVEL=DEBUG to see more detail.\n",
AssertionError: '/home/runner/work/hpecp-python-library/hp[246 chars]l.\n' != 'Could not connect to controller - set LOG[30 chars]l.\n'
- /home/runner/work/hpecp-python-library/hpecp-python-library/hpecp/client.py:147: ResourceWarning: unclosed file <_io.BufferedReader name='/tmp/tmpu6g84uk3'>
-   config.readfp(codecs.open(config_file, "r", "utf8"))
  Could not connect to controller - set LOG_LEVEL=DEBUG to see more detail.