[ruby-2.1.0] test on ruby 2.1.0, $SAFE level 4 was dropped
[ruby-2.1.0] ruby version conditional consistency
[ruby-2.1.0] lock rubygems at 2.1.11 to fix sort issues on 1.8.7
Merge pull request #679 from portertech/ruby-2.1.0

Test Sensu on Ruby 2.1.0, $SAFE level 4 was dropped