remove docker-toolbox for macOS as a viable way to use docker
remove docker-toolbox for macOS as a viable way to use docker

Change-Id: I9e38843083ea97045a817f0b13d73ba9c453ca10
Reviewed-on: https://gerrit.instructure.com/117888
Reviewed-by: Bryan Petty <33564f6eff3d808d3eaaa056a1631fdcde5faed6@instructure.com>
Product-Review: Tyler Pickett <3f20fcf21b1970c94966160adcf831eedd808a06@instructure.com>
QA-Review: Tyler Pickett <3f20fcf21b1970c94966160adcf831eedd808a06@instructure.com>
Tested-by: Tyler Pickett <3f20fcf21b1970c94966160adcf831eedd808a06@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,venturehive/canvas-lms,instructure/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,venturehive/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,venturehive/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms