Adjust scrutinizer settings to use external code coverage

[1] http://www.adayinthelifeof.nl/2013/11/20/external-code-coverage-with-travis-scrutinizer/
Merge pull request #49 from SemanticMediaWiki/scrutinizer

Adjust scrutinizer settings to use external code coverage
Merge branch 'master' of ssh://review/mediawiki/extensions/SemanticMediaWiki