Don't pass reference to mutable slice

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

pkg/registrar/registrar.go

@@ -98,7 +98,12 @@ func (r *Registrar) GetNames(key string) ([]string, error) {
 	if !exists {
 		return nil, ErrNoSuchKey
 	}
-	return names, nil
+
+	ls := make([]string, 0, len(names))
+	for _, n := range names {
+		ls = append(ls, n)
+	}
+	return ls, nil
 }
 
 // Get returns the key that the passed in name is reserved to