Add ability to suppress "Ruby 2.5 support is untested" message
Add ability to suppress "Ruby 2.5 support is untested" message

This message can interfere with certain text editors/tools that
read the application output. This gives users the option of
setting an environment variable to hide that message.

Change-Id: I8033fd61c381c3628be0430f0d0b098a3bb42947
Reviewed-on: https://gerrit.instructure.com/137784
Reviewed-by: James Williams  <3a5f4ed991dbfa5c9ef76ad729d240ca12f62180@instructure.com>
Tested-by: Jenkins
Product-Review: Dan Minkevitch <2591e5f46f28d303f9dc027d475a5c60d8dea17a@instructure.com>
QA-Review: Dan Minkevitch <2591e5f46f28d303f9dc027d475a5c60d8dea17a@instructure.com>

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