tests: IdentityManagementFixture no longer derives from BaseFixture

Also rename it to KeyChainFixture

Refs: #4528
Change-Id: Id86f4affc9c4c9ae159912430cc3e78557bf1ac2
diff --git a/tests/daemon/mgmt/manager-common-fixture.hpp b/tests/daemon/mgmt/manager-common-fixture.hpp
index 8725680..a12d671 100644
--- a/tests/daemon/mgmt/manager-common-fixture.hpp
+++ b/tests/daemon/mgmt/manager-common-fixture.hpp
@@ -29,7 +29,7 @@
 #include "mgmt/manager-base.hpp"
 #include "fw/forwarder.hpp"
 
-#include "tests/identity-management-fixture.hpp"
+#include "tests/key-chain-fixture.hpp"
 
 #include <ndn-cxx/security/command-interest-signer.hpp>
 #include <ndn-cxx/util/dummy-client-face.hpp>
@@ -39,7 +39,7 @@
 
 /** \brief A fixture that provides a CommandInterestSigner.
  */
-class CommandInterestSignerFixture : public IdentityManagementTimeFixture
+class CommandInterestSignerFixture : public UnitTestTimeFixture, public KeyChainFixture
 {
 protected:
   CommandInterestSignerFixture();