Abort in case job was not saved successfully

Whenever I attempt to save job configuration from scenario I got `Error 400: Exception: This page expects a form submission` (using either firefox or chrome). Obviously, the configuration is not saved and scenario is going to fail on the first step that relies on saved configuration with unhelpful or misleading message.

This is not a fix it just make the scenario fail noisily and as soon as possible in aforementioned situation.