[Python] Python track2 autorest tools generate surplus files

[msyyc]

Describe the bug

Please provide as much information as you can. This would be: 
- OpenAPI files having the issues
- Autorest command used

ENV: Linux
Python:3.6.9
Command:/usr/local/bin/autorest //azure-rest-api-specs/specification/digitaltwins/resource-manager/readme.md --multiapi --python --python-mode=update --python-sdks-folder=//azure-sdk-for-python/sdk --track2 --use=@autorest/python@5.4.3 --version=3.0.6272

(azure-rest-api-specs repo: https://github.com/Azure/azure-rest-api-specs.git)
(azure-sdk-for-python repo : https://github.com/Azure/azure-sdk-for-python.git)

Expected behavior
The necessary Python code file is generated

ERROR

Additional context
Add any other context about the problem here.

[iscai-msft]

@msyyc we're generatign a version file for digitaltwins because a package-versionn is present in the config file. We only generate a version file if a package-version is specified (though you can keep a current versioin file you already have with flag keep-version-file. Closinig this issue bc this behavior is expected