Restrict pipeline testing to versions 5 and up

Author: tylerjl

spec/acceptance/tests/acceptance_spec.rb

@@ -90,7 +90,7 @@
 
   include_examples('template operations', es_01, v[:template])
 
-  include_examples('pipeline operations', es_01, v[:pipeline])
+  include_examples('pipeline operations', es_01, v[:pipeline]) if semver(v[:elasticsearch_full_version]) >= semver('5.0.0')
 
   include_examples('plugin acceptance tests', v[:elasticsearch_plugins]) unless v[:elasticsearch_plugins].empty?