Keeping the jQuery chain from breaking.

This plugin was not returning the DOM reference itself, but the parent so if you were trying to use the DOM element and then setting the value in a different line using the same variable, it was not really going to be possible.

Example:
$cpuUtilizationCircleProgress = $('.circle-progress').knob();
$cpuUtilizationCircleProgress.val(20).trigger('change');

The second line wasn't going to do nothing since the $cpuUtilizationCircleProgress variable were getting the wrong DOM reference from jQuery-Knob in the first line.