Don't leave discovered infra providers

<strike>When infra providers are discovered, they have a different name than when the auto creates them.  We will now keep track of what a provider's name is when discovered, and when we ask if the provider already exists in CFME, we'll check the discovered name too.  (in the yaml this name is `default_name`).</strike>

<strike>Not sure if this applies at all to cloud providers, there's no other fields in the yaml so i'll assume that both names are equal unless someone tells me otherwise.</strike>

The above technique probably won't work well, there's still code that depends on the yaml name.  Just blow away discovered providers after the test is over.