Fix garden-cni pre-start to not fail if it can't clean up everything
Fix garden-cni pre-start to not fail if it can't clean up everything

[#148173051]

cloudfoundry-incubator/cf-networking-release,cloudfoundry-incubator/cf-networking-release,cloudfoundry-incubator/cf-networking-release,cloudfoundry-incubator/cf-networking-release