NPE on tagged logger

[lanxx019]

We have a lot of test failures on this:

      NoMethodError:
        undefined method `size' for nil:NilClass
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/logstash-logger-0.22.1/lib/logstash-logger/tagged_logging.rb:18:in `ensure in tagged'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/logstash-logger-0.22.1/lib/logstash-logger/tagged_logging.rb:18:in `tagged'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/logstash-logger-0.22.1/lib/logstash-logger/tagged_logging.rb:5:in `tagged'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/railties-4.0.13/lib/rails/rack/logger.rb:20:in `call'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/rack-1.5.5/lib/rack/session/abstract/id.rb:225:in `context'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/rack-1.5.5/lib/rack/session/abstract/id.rb:220:in `call'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/actionpack-4.0.13/lib/action_dispatch/middleware/cookies.rb:486:in `call'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/request_store-1.3.1/lib/request_store/middleware.rb:9:in `call'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/actionpack-4.0.13/lib/action_dispatch/middleware/request_id.rb:21:in `call'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/rack-1.5.5/lib/rack/methodoverride.rb:21:in `call'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/rack-1.5.5/lib/rack/runtime.rb:17:in `call'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/activesupport-4.0.13/lib/active_support/cache/strategy/local_cache.rb:83:in `call'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/actionpack-4.0.13/lib/action_dispatch/middleware/static.rb:84:in `call'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/rack-1.5.5/lib/rack/sendfile.rb:112:in `call'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/rack-cors-0.4.0/lib/rack/cors.rb:80:in `call'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/railties-4.0.13/lib/rails/engine.rb:511:in `call'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/railties-4.0.13/lib/rails/application.rb:97:in `call'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/rack-test-0.6.3/lib/rack/mock_session.rb:30:in `request'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/rack-test-0.6.3/lib/rack/test.rb:244:in `process_request'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/rack-test-0.6.3/lib/rack/test.rb:124:in `request'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/actionpack-4.0.13/lib/action_dispatch/testing/integration.rb:311:in `process'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/actionpack-4.0.13/lib/action_dispatch/testing/integration.rb:32:in `get'
      # /home/vagrant/.rvm/gems/ruby-2.2.3/gems/actionpack-4.0.13/lib/action_dispatch/testing/integration.rb:345:in `block (2 levels) in <module:Runner>'
      # ./spec/requests/stark/stark_helper.rb:51:in `stark_request'
      # ./spec/requests/stark/stark_helper.rb:19:in `stark_get'
      # ./spec/requests/stark/dashboard_shipment_list_spec.rb:7:in `block (2 levels) in <top (required)>'
      # ./spec/requests/stark/dashboard_shipment_list_spec.rb:81:in `block (5 levels) in <top (required)>'
      # ------------------
      # --- Caused by: ---
      # NoMethodError:
      #   undefined method `empty?' for nil:NilClass
      #   /home/vagrant/.rvm/gems/ruby-2.2.3/gems/logstash-logger-0.22.1/lib/logstash-logger/tagged_logging.rb:22:in `reject'

I do not know or care why we are getting nil tags, but I think it would be save to check it inside the reject block here

[dwbutler]

Fixed in #124