Free calloc()'d pointer correctly in wxFSWatchEntryMSW.

OVERLAPPED struct was allocated using calloc() but deleted later. Fix this by
deallocating it with free() instead.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67806 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/private/fswatcher.h

@@ -50,7 +50,7 @@ public:
                                 m_path);
             }
         }
-        delete m_overlapped;
+        free(m_overlapped);
     }
 
     bool IsOk() const