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

vendor/github.com/libopenstorage/openstorage/api/status.go

@@ -0,0 +1,49 @@
+package api
+
+type StatusKind int32
+
+const (
+	// StatusSeverityLow indicates an OK status
+	StatusSeverityLow StatusKind = iota
+	// StatusSeverityMedium indicates a status which is in transition from OK to BAD or vice versa
+	StatusSeverityMedium
+	// StatusSeverityHigh indicates a BAD status
+	StatusSeverityHigh
+)
+
+var statusToStatusKind = map[Status]StatusKind{
+	Status_STATUS_NONE:              StatusSeverityHigh,
+	Status_STATUS_INIT:              StatusSeverityMedium,
+	Status_STATUS_OK:                StatusSeverityLow,
+	Status_STATUS_OFFLINE:           StatusSeverityHigh,
+	Status_STATUS_ERROR:             StatusSeverityHigh,
+	Status_STATUS_NOT_IN_QUORUM:     StatusSeverityHigh,
+	Status_STATUS_DECOMMISSION:      StatusSeverityHigh,
+	Status_STATUS_MAINTENANCE:       StatusSeverityHigh,
+	Status_STATUS_STORAGE_DOWN:      StatusSeverityHigh,
+	Status_STATUS_STORAGE_DEGRADED:  StatusSeverityHigh,
+	Status_STATUS_NEEDS_REBOOT:      StatusSeverityHigh,
+	Status_STATUS_STORAGE_REBALANCE: StatusSeverityMedium,
+	Status_STATUS_STORAGE_DRIVE_REPLACE:     StatusSeverityMedium,
+	// Add statuses before MAX
+	Status_STATUS_MAX: StatusSeverityHigh,
+}
+
+func StatusSimpleValueOf(s string) (Status, error) {
+	obj, err := simpleValueOf("status", Status_value, s)
+	return Status(obj), err
+}
+
+func (x Status) SimpleString() string {
+	return simpleString("status", Status_name, int32(x))
+}
+
+func (x Status) StatusKind() StatusKind {
+	statusType, _ := statusToStatusKind[x]
+	return statusType
+}
+
+// StatusKindMapLength used only for unit testing
+func StatusKindMapLength() int {
+	return len(statusToStatusKind)
+}