Remove redundant void in task

It is not required.  Also, move the deleted destructor to a public
member where it should be.

Tested:
Code builds.  No functional changes.

Signed-off-by: Ed Tanous <ed@tanous.net>
Change-Id: I4b04ee0870e908fb8204d91e2cd8505518272c7a
diff --git a/redfish-core/lib/task.hpp b/redfish-core/lib/task.hpp
index 5698bc9..e18168b 100644
--- a/redfish-core/lib/task.hpp
+++ b/redfish-core/lib/task.hpp
@@ -102,9 +102,10 @@
         timer(crow::connections::systemBus->get_io_context())
 
     {}
-    TaskData() = delete;
 
   public:
+    TaskData() = delete;
+
     static std::shared_ptr<TaskData>& createTask(
         std::function<bool(boost::system::error_code,
                            sdbusplus::message::message&,
@@ -161,7 +162,7 @@
         }
     }
 
-    void finishTask(void)
+    void finishTask()
     {
         endTime = std::chrono::system_clock::to_time_t(
             std::chrono::system_clock::now());