Check whether CAStore is available in compile-time

[v0idpwn]

Removes the cost of calling Code.ensure_loaded?/1 every time that credentials are not provided.

[coveralls]

Pull Request Test Coverage Report for Build 1dbeeeea825c06aa4a60aabbe1a053f358d08bd2-PR-428

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.06%) to 87.879%

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Totals
Change from base Build 530ba279d919b17a903f10ac9aeb39baf8c019e3:	0.06%
Covered Lines:	1276
Relevant Lines:	1452

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💛 - Coveralls

[whatyouhide]

Good catch, thanks @v0idpwn 💟