specinfra 0.5.0 has made some changes that break run_command for us,
get the ret from CommandResult.new now.
Merge pull request #15 from apenney/fix-serverspec

specinfra 0.5.0 has made some changes that break run_command for us,
Update argument passing for RS_DESTROY
Merge pull request #16 from hunner/preserve_hosts

Update argument passing for RS_DESTROY