bug#32673: 27.0.50; wdired: broken 'wdired--restore-dired-filename-prop'

[Juri Linkov]

As reported in 
https://lists.gnu.org/archive/html/emacs-devel/2018-09/msg00372.html
Wdired breaks delete-selection-mode in the latest master 27.0.50:

1. create scratch directory with a file

   mkdir /tmp/test
   cd /tmp/test
   touch foo.c

2. start emacs

   LC_ALL=C emacs -Q -nw

3. activate delete-selection-mode

   M-x delete-selection-mode RET

4. go into the folder

   C-x C-f /tmp/test

5. enter wdired mode

   C-x C-q

6. replace 'foo' with 'test' by selecting the whole file name
   and typing a new one, e.g.

   M-2 C-M-SPC test

   or

   C-SPC C-e test

When typing the first letter, it removes delete-selection-pre-hook from
pre-command-hook, thus breaking delete-selection-mode, because of this
error seen in the *Messages* buffer:

  Error in pre-command-hook (delete-selection-pre-hook): (error "No file on 
this line")

The same error is reproducible when simply deleting an old file name
before typing a new one in the step 6, e.g.:

   M-d test

The raised error is:

  Debugger entered--Lisp error: (error "No file on this line")
    signal(error ("No file on this line"))
    error("%s" "No file on this line")
    dired-move-to-end-of-filename(nil)
    dired-get-filename()
    wdired--restore-dired-filename-prop(198 198 1)
    delete-char(1 nil)
    funcall-interactively(delete-char 1 nil)
    call-interactively(delete-char nil nil)
    command-execute(delete-char)

This is caused by changes in bug#32173.