adjust bundler version range
adjust bundler version range

When bundler 1.17 is released, this will likely result in the same build
failures seen prior to this change.

test plan:
 * Verify Jenkins passes

Change-Id: I4be0fb3f9a8c2ca072e04ecff7f7cba3e055da61
Reviewed-on: https://gerrit.instructure.com/150711
Tested-by: Jenkins
Reviewed-by: Simon Williams <088e16a1019277b15d58faf0541e11910eb756f6@instructure.com>
Product-Review: Jeremy Neander <20252aad5efdc666f083d82ab63ed0f9f72a043e@instructure.com>
QA-Review: Jeremy Neander <20252aad5efdc666f083d82ab63ed0f9f72a043e@instructure.com>

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