Portworx Volume Driver in Kubernetes

- Add a new type PortworxVolumeSource
- Implement the kubernetes volume plugin for Portworx Volumes under pkg/volume/portworx
- The Portworx Volume Driver uses the libopenstorage/openstorage specifications and apis for volume operations.

Changes for k8s configuration and examples for portworx volumes.

- Add PortworxVolume hooks in kubectl, kube-controller-manager and validation.
- Add a README for PortworxVolume usage as PVs, PVCs and StorageClass.
- Add example spec files

Handle code review comments.

- Modified READMEs to incorporate to suggestions.
- Add a test for ReadWriteMany access mode.
- Use util.UnmountPath in TearDown.
- Add ReadOnly flag to PortworxVolumeSource
- Use hostname:port instead of unix sockets
- Delete the mount dir in TearDown.
- Fix link issue in persistentvolumes README
- In unit test check for mountpath after Setup is done.
- Add PVC Claim Name as a Portworx Volume Label

Generated code and documentation.
- Updated swagger spec
- Updated api-reference docs
- Updated generated code under pkg/api/v1

Godeps update for Portworx Volume Driver
- Adds github.com/libopenstorage/openstorage
- Adds go.pedge.io/pb/go/google/protobuf
- Updates Godep Licenses

pkg/security/podsecuritypolicy/util/util.go

@@ -63,6 +63,7 @@ func GetAllFSTypesAsSet() sets.String {
 		string(extensions.AzureDisk),
 		string(extensions.PhotonPersistentDisk),
 		string(extensions.Projected),
+		string(extensions.PortworxVolume),
 	)
 	return fstypes
 }
@@ -118,6 +119,8 @@ func GetVolumeFSType(v api.Volume) (extensions.FSType, error) {
 		return extensions.PhotonPersistentDisk, nil
 	case v.Projected != nil:
 		return extensions.Projected, nil
+	case v.PortworxVolume != nil:
+		return extensions.PortworxVolume, nil
 	}
 
 	return "", fmt.Errorf("unknown volume type for volume: %#v", v)