chore(CVR): enable REBUILD_ESTIMATES feature gate

[mittachaitu]

Signed-off-by: mittachaitu sai.chaithanya@mayadata.io

What this PR does / why we need it:

• Enables the feature gate REBUILD_ESTIMATES by default(previous PRs feat(snapList): add snapshots information on CVR #1639, feat(pendingsnapshots): add pending snapshots on CVR by talking to peer replicas #1641).
• Removes extra fields under CVR.Status.Snapshots, current it has only LogicalReferenced.
  LogicalReferenced: Size in bytes of the volume when the snapshot was taken.

Example CVR YAML:

apiVersion: openebs.io/v1alpha1
kind: CStorVolumeReplica
metadata:
  annotations:
    cstorpool.openebs.io/hostname: 127.0.0.1
    isRestoreVol: "false"
    openebs.io/storage-class-ref: |
      name: single-sc
      resourceVersion: 20797
  creationTimestamp: "2020-04-15T18:20:34Z"
  finalizers:
  - cstorvolumereplica.openebs.io/finalizer
  generation: 27
  labels:
    cstorpool.openebs.io/name: cstor-sparse-pool-g45t
    cstorpool.openebs.io/uid: fab7b50f-29ea-495b-bfc4-cd256ccb1d27
    cstorvolume.openebs.io/name: pvc-15ec16c1-49a6-43be-ad26-e1ce4229b7e7
    openebs.io/cas-template-name: cstor-volume-create-default-1.9.0
    openebs.io/persistent-volume: pvc-15ec16c1-49a6-43be-ad26-e1ce4229b7e7
    openebs.io/version: 1.9.0
  name: pvc-15ec16c1-49a6-43be-ad26-e1ce4229b7e7-cstor-sparse-pool-g45t
  namespace: openebs
  resourceVersion: "22857"
  selfLink: /apis/openebs.io/v1alpha1/namespaces/openebs/cstorvolumereplicas/pvc-15ec16c1-49a6-43be-ad26-e1ce4229b7e7-cstor-sparse-pool-g45t
  uid: 03f5be25-4ada-4dba-bb79-b5858f99e8d7
spec:
  capacity: 5G
  replicaid: 1733F78111FE8F998284A7DA13998CF5
  targetIP: 10.0.0.133
  zvolWorkers: ""
status:
  capacity:
    totalAllocated: 6K
    used: 6K
  lastTransitionTime: "2020-04-15T18:29:23Z"
  lastUpdateTime: "2020-04-15T18:38:48Z"
  phase: Healthy
  pendingSnapshots:
    vol1_snap3:
      logicalReferenced: 417277952
  snapshots:
    vol1_snap2:
      logicalReferenced: 6144
versionDetails:
  autoUpgrade: false
  desired: 1.9.0
  status:
    current: 1.9.0
    dependentsUpgraded: true
    lastUpdateTime: null
    state: ""

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

Special notes for your reviewer:

• As of now used value under the snapshot will not increase(need to fix it).

Release Note:

• Enables REBUILD_ESTIMATES feature gate by default so that CVR status will have a list of snapshots and pending snapshots. The list under snapshots represents snapshots created for that volume and pendingSnapshots represents snapshots that are yet to rebuild from the peer replicas.

Checklist:

• Fixes #
• Labelled this PR & related issue with documentation tag
• PR messages has document related information
• Labelled this PR & related issue with breaking-changes tag
• PR messages has breaking changes related information
• Labelled this PR & related issue with requires-upgrade tag
• PR messages has upgrade related information
• Commit has unit tests
• Commit has integration tests

[vishnuitta]

changes are good.. one minor comment on log level

[vishnuitta]

changes are good