GeckoDriver (firefox) logging causes exceptions

[ghost]

Bug

When running a test in Firefox (geckodriver), if there is anything printed to the console during the test, an UnsupportedCommandException exception will be thrown causing the test to fail. Geckodriver maintainers have stated they are not going to implement logging features until W3C finalizes a standard for it mozilla/geckodriver#284

Expected

If browser logging is unavailable then log a statement regarding the console output being discarded and continue the test.

Repro

1. set the browser to firefox
2. open a site which will generate a log to console
3. See error

org.openqa.selenium.UnsupportedCommandException: POST /session/XXXXXXXX-XXXX-XXXX-XXXX-XXXXc43ed72f/log did not match a known command
Using Selenium Build info: version: '3.141.59', revision: 'e82be7d358', time: '2018-11-14T08:17:03' on Saucelabs