[STORE] Added cluster.health wait_for_status: 'yellow' to Repository integration test

Trying to prevent errors on the Jenkins machine such as:

    1) Failure:
    test_: The default repository class should pass options to save and find. (Elasticsearch::Persistence::RepositoryDefaultClassIntegrationTest) [/home/jenkins/workspace/es-rails_core/ES_V/1.x_nightly/GEMFILE/4.0.gemfile/RUBY_V/1.9.3-p551/jdk/JDK7/label/metal-pool/elasticsearch-persistence/test/integration/repository/default_class_test.rb:76]:
    [Elasticsearch::Persistence::Repository::DocumentNotFound] exception expected, not
    Class: <Elasticsearch::Transport::Transport::Errors::ServiceUnavailable>
    Message: <"[503] {\"error\":\"NoShardAvailableActionException[[repository][1] null]; nested: IllegalIndexShardStateException[[repository][1] CurrentState[POST_RECOVERY] operations only allowed when started/relocated]; \",\"status\":503}">

http://build-eu-00.elasticsearch.org/view/Clients/job/es-rails_core/ES_V=1.x_nightly,GEMFILE=4.0.gemfile,RUBY_V=1.9.3-p551,jdk=JDK7,label=metal-pool/lastBuild/console

Author: karmi

elasticsearch-persistence/test/integration/repository/default_class_test.rb

@@ -73,6 +73,8 @@ def to_hash
           note = Note.new(id: '1', title: 'Test')
           @repository.save note, routing: 'ABC'
 
+          @repository.client.cluster.health level: 'indices', wait_for_status: 'yellow'
+
           assert_raise Elasticsearch::Persistence::Repository::DocumentNotFound do
             @repository.find(1, routing: 'DEF')
           end