Add missing viper config for etcd user/pass

[rsafonseca]

backport #421

[coveralls]

Pull Request Test Coverage Report for Build 19577241948

Details

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• 21 unchanged lines in 3 files lost coverage.
• Overall coverage decreased (-0.2%) to 61.747%

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Files with Coverage Reduction	New Missed Lines	%
modules/binary.go	2	78.26%
module.go	6	62.64%
app.go	13	72.36%

Totals
Change from base Build 19569775682:	-0.2%
Covered Lines:	5154
Relevant Lines:	8347

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💛 - Coveralls