fix issue w/ outputDir in case of using code-signing

[sergey-akhalkov]

relates to #544

[sergey-akhalkov]

@max-mironov, @ruslan-bikkinin JFYI - going to fix the same in the https://github.com/Microsoft/appcenter-cli after approval from @PaperMonster that the issue is fixed w/ this PR

[shashankwadi]

Is this Fixed? Not working for mw still RN version is .51

[SudoPlz]

Hey @sergey-akhalkov @max-mironov , thanks for all the great work.
Does this PR mean that the path will always be <ourBuildOutputPath>/CodePush/

Looks like the CodePush/ dir is always created and appended to our build output path.

Thanks