Clear OpenSSL error queue if rdrand engine is unavailable

[olszomal]

ENGINE_by_id("rdrand") may leave an error in the OpenSSL error queue when the engine is not present, which is an expected condition.

Clear the error queue in this case to avoid propagating stale errors from the error queue to subsequent OpenSSL operations.

Summary by CodeRabbit

• Bug Fixes
  • Enhanced error handling during cryptographic component initialization when unavailable.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 2c1e94c5-2ef1-412e-80e0-9d1cfe47b641

📥 Commits

Reviewing files that changed from the base of the PR and between 5a3466f and ca71372.

📒 Files selected for processing (1)

• src/lib/crypto/OSSLCryptoFactory.cpp

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📝 Walkthrough

Walkthrough

Added error queue cleanup via ERR_clear_error() in the OSSLCryptoFactory constructor when RDRAND engine initialization is unavailable. This prevents stale error states from persisting when the engine lookup fails.

Changes

Cohort / File(s)	Summary
RDRAND Engine Error Handling src/lib/crypto/OSSLCryptoFactory.cpp	Added explicit OpenSSL error queue cleanup when RDRAND engine is unavailable in constructor initialization under WITH_ENGINES condition.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Poem

🐰 When engines won't appear, don't let errors linger here,
Clear the queue with gentle care, so no stale state will dare!
A rabbit's fix, both small and spry, ensures the code stays spry. ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately and concisely summarizes the main change: adding error queue cleanup when the rdrand engine is unavailable.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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