Add callback support to triggerable actions

Change-Id: Icc27fbe9403eda418f41e12c76af7f3216f4b72a
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/bmc/test/triggerable_mock.hpp b/bmc/test/triggerable_mock.hpp
index 9a63dcb..de2b025 100644
--- a/bmc/test/triggerable_mock.hpp
+++ b/bmc/test/triggerable_mock.hpp
@@ -18,6 +18,7 @@
     MOCK_METHOD0(trigger, bool());
     MOCK_METHOD0(abort, void());
     MOCK_METHOD0(status, ActionStatus());
+    using TriggerableActionInterface::cb;
 };
 
 std::unique_ptr<TriggerableActionInterface> CreateTriggerMock()