tests: sign command Interests with CommandInterestSigner

Previously used ndn::v2::KeyChain::sign creates signed Interests, not
command Interests.

refs #4089

Change-Id: I7b13926d676ff81041f036eaec1978d82e8e1dfd
diff --git a/tests/daemon/mgmt/face-manager-command-fixture.hpp b/tests/daemon/mgmt/face-manager-command-fixture.hpp
index bf376f5..b00b9cc 100644
--- a/tests/daemon/mgmt/face-manager-command-fixture.hpp
+++ b/tests/daemon/mgmt/face-manager-command-fixture.hpp
@@ -29,10 +29,7 @@
 #include "mgmt/face-manager.hpp"
 #include "fw/face-table.hpp"
 
-#include "tests/identity-management-fixture.hpp"
-
-#include <ndn-cxx/mgmt/dispatcher.hpp>
-#include <ndn-cxx/util/dummy-client-face.hpp>
+#include "tests/manager-common-fixture.hpp"
 
 namespace nfd {
 namespace tests {
@@ -61,7 +58,7 @@
   FaceManager manager;
 };
 
-class FaceManagerCommandFixture : public IdentityManagementTimeFixture
+class FaceManagerCommandFixture : public CommandInterestSignerFixture
 {
 public:
   FaceManagerCommandFixture();