Some changes on sign cmd and config

[ligangty]

No description provided.

[yma955]

@ligangty If no Optional to initialize the __radas_config, I'm afraid it will report AttributeError: CharonConfig object has no attribute radas_config when the method get_radas_config is called without radas_config there, we have some places that call this method.

[ligangty]

Sounds reasonable. I'll correct it. Thanks

[coveralls]

Pull Request Test Coverage Report for Build 15249017201

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 9 of 18 (50.0%) changed or added relevant lines in 3 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.04%) to 63.927%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
charon/pkgs/radas_signature_handler.py	3	4	75.0%
charon/cmd/cmd_sign.py	0	8	0.0%

Files with Coverage Reduction	New Missed Lines	%
charon/cmd/cmd_sign.py	1	0.0%

Totals
Change from base Build 15180796871:	-0.04%
Covered Lines:	2038
Relevant Lines:	3188

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💛 - Coveralls