PV controller: resync informers manually

We want relatively short resync period of PV/PVCs and at the same time we
don't want to force such short resync to all shared informer consumers.
Therefore we need to make our own periodic resync.

pkg/controller/volume/persistentvolume/pv_controller.go

@@ -164,6 +164,7 @@ type PersistentVolumeController struct {
 	volumePluginMgr           vol.VolumePluginMgr
 	enableDynamicProvisioning bool
 	clusterName               string
+	resyncPeriod              time.Duration
 
 	// Cache of the last known version of volumes and claims. This cache is
 	// thread safe as long as the volumes/claims there are not modified, they