Auto merge of #4744 - eagletmt:fix-rack2-failures, r=segiddins
Auto merge of #4744 - eagletmt:fix-rack2-failures, r=segiddins

Fix test failures due to Rack 2.x

- Rack 2.x requires Ruby version >= 2.2.2
- artifice doesn't support rack 2.x now.

mvz/bundler,asutoshpalai/bundler,RochesterinNYC/bundler,asutoshpalai/bundler,bundler/bundler,RochesterinNYC/bundler,dilumnavanjana/bundler,bundler/bundler,mvz/bundler,dilumnavanjana/bundler