build: require OpenSSL >= 1.1.1

Change-Id: I17a09ac60b867617af7a49fe19ab6e906dc14f61
diff --git a/tests/unit/util/random.t.cpp b/tests/unit/util/random.t.cpp
index bfa486a..73c3825 100644
--- a/tests/unit/util/random.t.cpp
+++ b/tests/unit/util/random.t.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2021 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).
  *
@@ -68,18 +68,11 @@
   }
 
 private: // RAND_METHOD callbacks
-#if OPENSSL_VERSION_NUMBER < 0x1010000fL
-  static void
-  seed(const void* buf, int num)
-  {
-  }
-#else
   static int
   seed(const void* buf, int num)
   {
     return 0;
   }
-#endif // OPENSSL_VERSION_NUMBER < 0x1010000fL
 
   static int
   bytes(unsigned char* buf, int num)
@@ -92,18 +85,11 @@
   {
   }
 
-#if OPENSSL_VERSION_NUMBER < 0x1010000fL
-  static void
-  add(const void* buf, int num, double entropy)
-  {
-  }
-#else
   static int
   add(const void* buf, int num, double entropy)
   {
     return 0;
   }
-#endif // OPENSSL_VERSION_NUMBER < 0x1010000fL
 
   static int
   pseudorand(unsigned char* buf, int num)