FTP: Fixed backtrace in debug code [bug 7293].

Stdio.File()->query_address() throws errors if the file isn't open.
Merge branch 'patches/bug7293' into devel

* patches/bug7293:
  FTP: Fixed backtrace in debug code [bug 7293].
Version bumped to 5.5.35 by buildsystem.
Version bumped to 5.5.36 by buildsystem.