Fix const correctness issues

cppcheck correctly notes that a lot of variables in the new code can be
const.  Make most of them const.

Tested: WIP

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I8f37b6353fd707923f533e1d61c5b5419282bf23
diff --git a/redfish-core/lib/task.hpp b/redfish-core/lib/task.hpp
index dcad059..8892614 100644
--- a/redfish-core/lib/task.hpp
+++ b/redfish-core/lib/task.hpp
@@ -120,7 +120,7 @@
 
         if (tasks.size() >= maxTaskCount)
         {
-            auto& last = tasks.front();
+            const auto& last = tasks.front();
 
             // destroy all references
             last->timer.cancel();
@@ -389,7 +389,7 @@
             return;
         }
 
-        std::shared_ptr<task::TaskData>& ptr = *find;
+        const std::shared_ptr<task::TaskData>& ptr = *find;
 
         asyncResp->res.jsonValue["@odata.type"] = "#Task.v1_4_3.Task";
         asyncResp->res.jsonValue["Id"] = strParam;