Try to clean up coveralls stuff to only happen when needed

[coveralls]

Pull Request Test Coverage Report for Build 31

• 0 of 0 (NaN%) changed or added relevant lines in 0 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-3.3%) to 73.333%

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Files with Coverage Reduction	New Missed Lines	%
src/ecc_compact.erl	1	73.33%
<!--	Total:	1		-->

Totals
Change from base Build 27:	-3.3%
Covered Lines:	22
Relevant Lines:	30

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💛 - Coveralls