Objects from shared informer must not be changed, they are shared among all
controllers.

This fixes CacheMutationDetector panic with this output:

CACHE *api.Node[5] ALTERED!
{"metadata":{"name":"ip-172-18-8-71.ec2.internal","selfLink":"/api/v1/nodes/ip-172-18-8-71.ec2.internal","uid":"73d07d16-976e-11e6-8225-0e2f14b56070","resourceVersion":"136","creationTimestamp":"2016-10-21T09:12:12Z","labels":{"beta.kubernetes.io/arch":"amd64","beta.kubernetes.io/instance-type":"t2.medium","beta.kubernetes.io/os":"linux","failure-domain.beta.kubernetes.io/region":"us-east-1","failure-domain.beta.kubernetes.io/zone":"us-east-1d","kubernetes.io/hostname":"ip-172-18-8-71.ec2.internal"},"annotations":{"volumes.kubernetes.io/controller-managed-attach-detach":"true"}},"spec":{"externalID":"i-9cb6180f","providerID":"aws:///us-east-1d/i-9cb6180f"},"status":{"capacity":{"alpha.kubernetes.io/nvidia-gpu":"0","cpu":"2","memory":"4045568Ki","pods":"110"},"allocatable":{"alpha.kubernetes.io/nvidia-gpu":"0","cpu":"2","memory":"4045568Ki","pods":"110"},"conditions":[{"type":"OutOfDisk","status":"False","lastHeartbeatTime":"2016-10-21T09:12:52Z","lastTransitionTime":"2016-10-21T09:12:12Z","reason":"KubeletHasSufficientDisk","message":"kubelet has sufficient disk space available"},{"type":"MemoryPressure","status":"False","lastHeartbeatTime":"2016-10-21T09:12:52Z","lastTransitionTime":"2016-10-21T09:12:12Z","reason":"KubeletHasSufficientMemory","message":"kubelet has sufficient memory available"},{"type":"DiskPressure","status":"False","lastHeartbeatTime":"2016-10-21T09:12:52Z","lastTransitionTime":"2016-10-21T09:12:12Z","reason":"KubeletHasNoDiskPressure","message":"kubelet has no disk pressure"},{"type":"InodePressure","status":"False","lastHeartbeatTime":"2016-10-21T09:12:52Z","lastTransitionTime":"2016-10-21T09:12:12Z","reason":"KubeletHasNoInodePressure","message":"kubelet has no inode pressure"},{"type":"Ready","status":"True","lastHeartbeatTime":"2016-10-21T09:12:52Z","lastTransitionTime":"2016-10-21T09:12:22Z","reason":"KubeletReady","message":"kubelet is posting ready status"}],"addresses":[{"type":"InternalIP","address":"172.18.8.71"},{"type":"LegacyHostIP","address":"172.18.8.71"},{"type":"ExternalIP","address":"54.85.104.236"}],"daemonEndpoints":{"kubeletEndpoint":{"Port":10250}},"nodeInfo":{"machineID":"78a79498db8e4fdc9ac24b5e436a982c","systemUUID":"EC2BB406-5467-4ABE-B54D-D9993C45714F","bootID":"2553d6b8-1ddb-4ef0-902a-d09a807b89ba","kernelVersion":"4.6.7-300.fc24.x86_64","osImage":"Fedora 24 (Cloud Edition)","containerRuntimeVersion":"docker://1.10.3","kubeletVersion":"v1.5.0-alpha.1.726+5aac5eddb809e4","kubeProxyVersion":"v1.5.0-alpha.1.726+5aac5eddb809e4","operatingSystem":"linux","architecture":"amd64"},"images":[{"names":["openshift/origin-release:latest"],"sizeBytes":714569002},{"names":["openshift/origin-haproxy-router-base:latest"],"sizeBytes":294417608},{"names":["openshift/origin-base:latest"],"sizeBytes":275310761},{"names":["docker.io/centos@sha256:2ae0d2c881c7123870114fb9cc7afabd1e31f9888dac8286884f6cf59373ed9b","docker.io/centos:centos7"],"sizeBytes":196744353},{"names":["gcr.io/google_containers/busybox@sha256:4bdd623e848417d96127e16037743f0cd8b528c026e9175e22a84f639eca58ff","gcr.io/google_containers/busybox:1.24"],"sizeBytes":1113554},{"names":["gcr.io/google_containers/pause-amd64@sha256:163ac025575b775d1c0f9bf0bdd0f086883171eb475b5068e7defa4ca9e76516","gcr.io/google_containers/pause-amd64:3.0"],"sizeBytes":746888}],"volumesInUse":["kubernetes.io/aws-ebs/aws://us-east-1d/vol-f4bd0352"]

A: ,"volumesAttached":[{"name":"kubernetes.io/aws-ebs/aws://us-east-1d/vol-f4bd0352","devicePath":"/dev/xvdba"}]}}

B: }}