BUG#25521 - optimize table, delete, show table status leads to table

            losing it's .MYD

When OPTIMIZE TABLE is completed it attempts to rename temporary
file to original name. This step may fail on windows when a file
is opened. As a result data file might be deleted and optimized
copy of file (table_name.MYD) remains.

This situation is handled properly by my_delete_allow_opened, so
use it instead of my_delete when attempting to rename a file on
windows.

No suitable test case for this bug.


mysys/my_redel.c:
  Attempting to delete an opened file and to immediately create
  a new one with the same name may result in my_redel failure on
  windows. It may fail because file is not deleted until it is
  closed.
  
  This situation is handled properly by my_delete_allow_opened, so
  use it instead of my_delete.

mysys/my_redel.c

@@ -60,7 +60,7 @@ int my_redel(const char *org_name, const char *tmp_name, myf MyFlags)
 		  MyFlags))
       goto end;
   }
-  else if (my_delete(org_name,MyFlags))
+  else if (my_delete_allow_opened(org_name, MyFlags))
       goto end;
   if (my_rename(tmp_name,org_name,MyFlags))
     goto end;