Add missing should in Array#permutation spec
Add missing should in Array#permutation spec

sgarciac/spec,eregon/rubyspec,ruby/spec,ruby/spec,sgarciac/spec,ruby/rubyspec,nobu/rubyspec,ruby/rubyspec,eregon/rubyspec,eregon/rubyspec,nobu/rubyspec,nobu/rubyspec,sgarciac/spec,ruby/spec