Automatic merge from submit-queue
Fill PV.Status.Message with deleter/recycler errors.
Instead of empty `Message` `kubectl describe pv` now shows:
```
Name: nfs
Labels: <none>
Status: Failed
Claim: default/nfs
Reclaim Policy: Recycle
Access Modes: RWX
Capacity: 1Mi
Message: Recycler failed: Pod was active on the node longer than specified deadline
Source:
Type: NFS (an NFS mount that lasts the lifetime of a pod)
Server: 10.999.999.999
Path: /
ReadOnly: false
```
This is actually a regression since 1.2
@kubernetes/sig-storage
- remove persistentvolume_ prefix from all files
- split controller.go into controller.go and controller_base.go (to have them
under 1500 lines for github)
