interest: remove deprecated setDefaultCanBePrefix()

Change-Id: Ifaffb7cc7772a31c3b396c60b816e783d70b7041
diff --git a/tests/unit/security/validator.t.cpp b/tests/unit/security/validator.t.cpp
index adf72d3..75ab618 100644
--- a/tests/unit/security/validator.t.cpp
+++ b/tests/unit/security/validator.t.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2020 Regents of the University of California.
+ * Copyright (c) 2013-2022 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -209,7 +209,6 @@
                         HierarchicalValidatorFixture<ValidationPolicySimpleHierarchyForInterestOnly>)
 {
   Interest interest("/Security/ValidatorFixture/Sub1/Sub2/Interest");
-  interest.setCanBePrefix(false);
   Data data("/Security/ValidatorFixture/Sub1/Sub2/Interest");
 
   VALIDATE_FAILURE(interest, "Unsigned");
@@ -218,7 +217,6 @@
   face.sentInterests.clear();
 
   interest = Interest("/Security/ValidatorFixture/Sub1/Sub2/Interest");
-  interest.setCanBePrefix(false);
   m_keyChain.sign(interest, signingWithSha256());
   m_keyChain.sign(data, signingWithSha256());
   VALIDATE_FAILURE(interest, "Required KeyLocator/Name missing (not passed to policy)");