ignore cleanup errors as observed on windows

[coveralls]

Pull Request Test Coverage Report for Build 3631510873

• 6 of 24 (25.0%) changed or added relevant lines in 2 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.9%) to 74.795%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
bep032tools/generator/tests/test_BEP032Generator.py	5	23	21.74%
<!--	Total:	6	24	25.0%	-->

Files with Coverage Reduction	New Missed Lines	%
bep032tools/generator/tests/test_BEP032Generator.py	1	93.73%
<!--	Total:	1		-->

Totals
Change from base Build 3574936814:	-0.9%
Covered Lines:	1095
Relevant Lines:	1464

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💛 - Coveralls