init: even better logging around subsequent sys.powerctl messages

Bug: 150863651
Test: add delays during critical parts of shutdown and see the
      expected debug information
Change-Id: Ida586903fd3eefc32ca9ee34ea2db037896ed9f4
diff --git a/init/init.h b/init/init.h
index 27f64e2..4f686cb 100644
--- a/init/init.h
+++ b/init/init.h
@@ -42,6 +42,8 @@
 void PropertyChanged(const std::string& name, const std::string& value);
 bool QueueControlMessage(const std::string& message, const std::string& name, pid_t pid, int fd);
 
+void DebugRebootLogging();
+
 int SecondStageMain(int argc, char** argv);
 
 }  // namespace init