failing specs under ng-pipeline

[colinsurprenant]

@andrewvc these specs failures seems related to ng-pipeline under master.

Using Accessor#strict_set for specs
Run options: exclude {:redis=>true, :socket=>true, :performance=>true, :couchdb=>true, :elasticsearch=>true, :elasticsearch_secure=>true, :export_cypher=>true, :integration=>true, :windows=>true}
FF.

Failures:

  1) LogStash::Inputs::Generator should generate configured message
     Failure/Error: Unable to find matching line from backtrace
     NoMethodError:
       undefined method `each' for nil:NilClass
     # ./logstash-core/lib/logstash/pipeline.rb:258:in `output_batch'
     # ./logstash-core/lib/logstash/pipeline.rb:255:in `output_batch'
     # ./logstash-core/lib/logstash/pipeline.rb:200:in `worker_loop'
     # ./logstash-core/lib/logstash/pipeline.rb:169:in `start_workers'

  2) LogStash::Inputs::Generator should generate message from stdin
     Failure/Error: Unable to find matching line from backtrace
     NoMethodError:
       undefined method `each' for nil:NilClass
     # ./logstash-core/lib/logstash/pipeline.rb:258:in `output_batch'
     # ./logstash-core/lib/logstash/pipeline.rb:255:in `output_batch'
     # ./logstash-core/lib/logstash/pipeline.rb:200:in `worker_loop'
     # ./logstash-core/lib/logstash/pipeline.rb:169:in `start_workers'

Finished in 0.786 seconds (files took 1.16 seconds to load)
3 examples, 2 failures

Failed examples:

rspec /Users/colin/dev/src/elasticsearch/logstash-plugins/logstash-input-generator/spec/inputs/generator_spec.rb:10 # LogStash::Inputs::Generator should generate configured message
rspec /Users/colin/dev/src/elasticsearch/logstash-plugins/logstash-input-generator/spec/inputs/generator_spec.rb:31 # LogStash::Inputs::Generator should generate message from stdin

Randomized with seed 37675