Fix references to non-existent local `slave_name` variable
Fix references to non-existent local `slave_name` variable

Related story:
  http://www.pivotaltracker.com/story/show/27318939 (fixed)
  ("Fix explosion in RSpec 2 `example_failed` method")

Change-Id: I719feb46a1022da636006a35994187707804d133
Reviewed-on: https://gerrit.causes.com/4685
Reviewed-by: Steve Dee <239b710744079cbd443875b57204a43cb15ab5d1@causes.com>
Tested-by: Greg Hurrell <79e2475f81a6317276bf7cbb3958b20d289b78df@causes.com>

causes/buffet,causes/buffet