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}
.F..F

Failures:

  1) LogStash::Inputs::Pipe pipe from echo should receive the pipe
     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::Pipe pipe from tail should receive all piped elements
     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 4.96 seconds (files took 0.882 seconds to load)
5 examples, 2 failures

Failed examples:

rspec /Users/colin/dev/src/elasticsearch/logstash-plugins/logstash-input-pipe/spec/inputs/pipe_spec.rb:44 # LogStash::Inputs::Pipe pipe from echo should receive the pipe
rspec /Users/colin/dev/src/elasticsearch/logstash-plugins/logstash-input-pipe/spec/inputs/pipe_spec.rb:76 # LogStash::Inputs::Pipe pipe from tail should receive all piped elements

Randomized with seed 18618