fix freespace for image GC

pkg/kubelet/images/image_gc_manager.go

@@ -351,7 +351,7 @@ func (im *realImageGCManager) freeSpace(bytesToFree int64, freeTime time.Time) (
 		// Images that are currently in used were given a newer lastUsed.
 		if image.lastUsed.Equal(freeTime) || image.lastUsed.After(freeTime) {
 			glog.V(5).Infof("Image ID %s has lastUsed=%v which is >= freeTime=%v, not eligible for garbage collection", image.id, image.lastUsed, freeTime)
-			break
+			continue
 		}
 
 		// Avoid garbage collect the image if the image is not old enough.