tidy up requires

It's really ugly to have to keep repeating File.dirname(__FILE__),
so we use a temporary variable, even in the case of a single require.
This minimises long "requires" lines and "requires" statements with
needing line-breaks, and should make search-and-replace a bit easier
if we later want to migrate to __dir__ (Ruby >= 2.0) or require_relative.

  http://stackoverflow.com/questions/4333286/ruby-require-vs-require-relative-best-practice-to-workaround-running-in-both

I've deliberately rejected the pattern:

  require File.expand_path('../relative/path', __FILE__)

because it relies on inconsistent semantics and inconsistent
documentation in File.expand_path:

  http://stackoverflow.com/questions/4333286/ruby-require-vs-require-relative-best-practice-to-workaround-running-in-both#comment34147297_4333552

spec/libraries/pacemaker/cib_object_spec.rb

@@ -1,8 +1,10 @@
-require 'spec_helper'
 require 'mixlib/shellout'
 
-require File.expand_path('../../../libraries/pacemaker', File.dirname(__FILE__))
-require File.expand_path('../../fixtures/keystone_primitive', File.dirname(__FILE__))
+require 'spec_helper'
+
+this_dir = File.dirname(__FILE__)
+require File.expand_path('../../../libraries/pacemaker', this_dir)
+require File.expand_path('../../fixtures/keystone_primitive', this_dir)
 
 describe Pacemaker::CIBObject do