Implements StatefulSet update

Implements history utilities for ControllerRevision in the controller/history package
StatefulSetStatus now has additional fields for consistency with DaemonSet and Deployment
StatefulSetStatus.Replicas now represents the current number of createdPods and StatefulSetStatus.ReadyReplicas is the current number of ready Pods

pkg/api/testing/fuzzer.go

@@ -723,6 +723,13 @@ func appsFuncs(t apitesting.TestingCommon) []interface{} {
 			if len(s.Spec.PodManagementPolicy) == 0 {
 				s.Spec.PodManagementPolicy = apps.OrderedReadyPodManagement
 			}
+			if len(s.Spec.UpdateStrategy.Type) == 0 {
+				s.Spec.UpdateStrategy.Type = apps.RollingUpdateStatefulSetStrategyType
+			}
+			if s.Spec.RevisionHistoryLimit == nil {
+				s.Spec.RevisionHistoryLimit = new(int32)
+				*s.Spec.RevisionHistoryLimit = 10
+			}
 		},
 	}
 }