A failing task extension produces zombi objects and resource leaks

[Sebastian Huber]

In _Thread_Initialize() we have this code:

  _Objects_Open_u32( &information->Objects, &the_thread->Object, config->name );

  /*
   *  We assume the Allocator Mutex is locked and dispatching is
   *  enabled when we get here.  We want to be able to run the
   *  user extensions with dispatching enabled.  The Allocator
   *  Mutex provides sufficient protection to let the user extensions
   *  run safely.
   */
  extension_status = _User_extensions_Thread_create( the_thread );
  if ( extension_status )
    return true;

If an extension fails, then the thread object is not closed. Also the delete extensions are not called. If a later create extension fails, the earlier create extensions may have allocated resources which could be freed by a corresponding delete extension.

[Sebastian Huber <sebastian.huber@…>]

In 1ac4a85/rtems:

score: Fix thread initialization

Close the thread object if a thread create extension fails. Also call
the delete extension to avoid resource leaks in early extensions if a
late extension fails.

Close #4270.