update header files in tests

Change-Id: Ibfffb9367349f58eeb193350bad34fdfccd8c553
diff --git a/tests/unit-tests/ca-memory.t.cpp b/tests/unit-tests/ca-memory.t.cpp
index c64d8f7..7425a0e 100644
--- a/tests/unit-tests/ca-memory.t.cpp
+++ b/tests/unit-tests/ca-memory.t.cpp
@@ -19,8 +19,8 @@
  */
 
 #include "ca-detail/ca-memory.hpp"
-#include "identity-management-fixture.hpp"
 #include "ca-detail/ca-sqlite.hpp"
+#include "test-common.hpp"
 
 namespace ndn {
 namespace ndncert {