[#42] registry: Do not create selectors without status filters

Should allow to catch bugs in scenarios earlier.

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

internal/registry/obj_selector.go

@@ -31,6 +31,9 @@ func NewObjSelector(registry *ObjRegistry, selectionSize int, filter *ObjFilter)
 	if selectionSize <= 0 {
 		selectionSize = objectSelectCache
 	}
+	if filter == nil || filter.Status == "" {
+		panic("filtering without status is not supported")
+	}
 	objSelector := &ObjSelector{
 		ctx:       registry.ctx,
 		boltDB:    registry.boltDB,