Retrieve the loopback_device when we are remounting
Retrieve the loopback_device when we are remounting

[finishes #98591514]

Signed-off-by: Svett Ralchev <da5e7676cee2b8579db636d977fd7d6ee8a31e38@pivotal.io>

cloudfoundry-incubator/garden-linux-release,totherme/garden-linux-release,luan/garden-linux-release,luan/garden-linux-release,cloudfoundry-incubator/garden-linux-release,tushar-dadlani/garden-linux-release,totherme/garden-linux-release,Pivotal-DataFabric/garden-linux-release,cloudfoundry-incubator/garden-linux-release,luan/garden-linux-release,Pivotal-DataFabric/garden-linux-release,tushar-dadlani/garden-linux-release,totherme/garden-linux-release,Pivotal-DataFabric/garden-linux-release,totherme/garden-linux-release,Pivotal-DataFabric/garden-linux-release,cloudfoundry-incubator/garden-linux-release,tushar-dadlani/garden-linux-release,luan/garden-linux-release,cloudfoundry-incubator/garden-linux-release,tushar-dadlani/garden-linux-release