Fix missing variable

7 jobs for master in 5 minutes and 44 seconds
Status Job ID Name Coverage
  Syntax 21
passed #229
ruby
ruby_2.1

00:00:09

 
  Syntax 22
passed #230
ruby
ruby_2.2

00:00:10

 
  Syntax 23
passed #231
ruby
ruby_2.3

00:00:10

 
  Syntax 24
passed #232
ruby
ruby_2.4

00:00:09

 
  Syntax J17
passed #233
ruby
jruby_1.7

00:02:04

 
  Syntax J91
passed #234
ruby
jruby_9.1

00:02:47

 
  Linting
passed #235
ruby
rubocop

00:00:12