encryptor: Properly handle KEK fetching notification

Change-Id: Id65b58d4a24cd79015fa5a6ab38994bb873af31f
Refs: #4669
diff --git a/src/encryptor.hpp b/src/encryptor.hpp
index 34d69bb..2b82d31 100644
--- a/src/encryptor.hpp
+++ b/src/encryptor.hpp
@@ -124,10 +124,10 @@
                            const ErrorCallback& onFailure,
                            size_t nTriesLeft);
 
-  void
+  bool
   makeAndPublishCkData(const ErrorCallback& onFailure);
 
-private:
+PUBLIC_WITH_TESTS_ELSE_PRIVATE:
   Name m_accessPrefix;
   Name m_ckPrefix;
   Name m_ckName;