@wilson 

This is part of the work to support ruby 1.9 in our stack, to be honest, I don't remember the ticket number.

I didn't know you patched dataflow, but the error below is what happens when we try to use dataflow with ruby 1.9:

```
/usr/local/ey_resin/ruby/lib/ruby/1.9.1/thread.rb:71:in `sleep': deadlock detected (fatal)
	from /usr/local/ey_resin/ruby/lib/ruby/1.9.1/thread.rb:71:in `wait'
	from /usr/local/ey_resin/ruby/lib/ruby/1.9.1/monitor.rb:110:in `wait'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/vendor/dataflow/dataflow.rb:102:in `block in __wait__'
	from /usr/local/ey_resin/ruby/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/vendor/dataflow/dataflow.rb:97:in `__wait__'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/vendor/dataflow/dataflow.rb:40:in `block in barrier'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/vendor/dataflow/dataflow.rb:40:in `each'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/vendor/dataflow/dataflow.rb:40:in `barrier'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/engineyard-serverside/task.rb:59:in `run_on_roles'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/engineyard-serverside/task.rb:45:in `run'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/engineyard-serverside/deploy.rb:196:in `block in ssh_executable'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/engineyard-serverside/task.rb:35:in `roles'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/engineyard-serverside/deploy.rb:195:in `ssh_executable'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/engineyard-serverside/strategies/git.rb:24:in `strategy'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/engineyard-serverside/strategies/git.rb:9:in `update_repository_cache'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/engineyard-serverside/deploy.rb:16:in `deploy'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/engineyard-serverside/cli.rb:68:in `deploy'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/vendor/thor/lib/thor/task.rb:33:in `run'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/vendor/thor/lib/thor/invocation.rb:109:in `block in invoke'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/vendor/thor/lib/thor/invocation.rb:116:in `call'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/vendor/thor/lib/thor/invocation.rb:116:in `invoke'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/vendor/thor/lib/thor.rb:137:in `block in start'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/vendor/thor/lib/thor/base.rb:378:in `start'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/vendor/thor/lib/thor.rb:124:in `start'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/lib/engineyard-serverside/cli.rb:10:in `start'
	from /usr/local/ey_resin/ruby/lib/ruby/gems/1.9.1/gems/engineyard-serverside-1.5.25.timestamps10/bin/engineyard-serverside:10:in `<top (required)>'
	from /usr/local/ey_resin/ruby/bin/engineyard-serverside:19:in `load'
	from /usr/local/ey_resin/ruby/bin/engineyard-serverside:19:in `<main>'
```