MQE-977: ErrorLogger expects source to be a log paramater

[imeron2433]

• update logger to validate param existence before using "source" param

Description

Fixed Issues (if relevant)

1. magento/magento2-functional-testing-framework#<issue_number>: Issue title
2. ...

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/verification tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)
• Changes to Framework doesn't have backward incompatible changes for tests or have related Pull Request with fixes to tests

[coveralls]

Coverage increased (+0.02%) to 50.349% when pulling 93f3b62 on MQE-977 into 1b40c8e on develop.