jobs/tsuru_beta: use other function name

Not sure if this has any impact on it, but here is a stack trace from
the scheduler:

2013-04-10 12:49:52 [app]: ================================================================================
2013-04-10 12:49:52 [app]: /home/application/current/vendor/bundle/ruby/1.9.1/gems/rufus-scheduler-2.0.18/lib/rufus/sc/scheduler.rb:416:in `block in trigger_job'
2013-04-10 12:49:52 [app]: /home/application/current/vendor/bundle/ruby/1.9.1/gems/rufus-scheduler-2.0.18/lib/rufus/sc/scheduler.rb:416:in `call'
2013-04-10 12:49:52 [app]: /home/application/current/vendor/bundle/ruby/1.9.1/gems/rufus-scheduler-2.0.18/lib/rufus/sc/jobs.rb:191:in `block in trigger'
2013-04-10 12:49:52 [app]: /home/application/current/vendor/bundle/ruby/1.9.1/gems/rufus-scheduler-2.0.18/lib/rufus/sc/jobs.rb:231:in `trigger_block'
2013-04-10 12:49:52 [app]: /home/application/current/vendor/bundle/ruby/1.9.1/gems/rufus-scheduler-2.0.18/lib/rufus/sc/jobs.rb:231:in `call'
2013-04-10 12:49:52 [app]: /home/application/current/jobs/milestones.rb:31:in `block in <top (required)>'
2013-04-10 12:49:52 [app]: /home/application/current/jobs/tsuru_beta.rb:9:in `fetch'
2013-04-10 12:49:52 [app]: wrong number of arguments (1 for 0)
2013-04-10 12:49:52 [app]: scheduler caught exception:
2013-04-10 12:49:52 [app]: ================================================================================