fix error  when gem install bundler

when i use:
    rvm_gem {
      'bundler':
      name => 'bundler',
      ruby_version => 'ree-1.8.7-2012.02',
      ensure => latest,
      require => Rvm_system_ruby['ree-1.8.7-2012.02'];
    }

it will hang on the blow command and will never go on.

debug: Rvm_gem[bundler](provider=gem): Executing '/usr/local/rvm/bin/rvm ree-1.8.7-2012.02 do gem list --local bundler$'
debug: Rvm_gem[bundler](provider=gem): Executing '/usr/local/rvm/bin/rvm ree-1.8.7-2012.02 do gem list --remote bundler$'