bug#22982: 25.0.92; Forms Mode seems to fail to open data file

[Eli Zaretskii]

> From: nljlistbox2@gmail.com (N. Jackson)
> Cc: 22982@debbugs.gnu.org,  john.b.mastro@gmail.com
> Date: Fri, 11 Mar 2016 12:11:20 -0400
> 
> 1.  emacs -Q
> 
> 2.  M-: (custom-set-variables '(major-mode (quote text-mode))) RET
> 
> 3.  M-x forms-find-file RET C-S-backspace ~/test-forms-control-file.el RET
> 
> 
> This recipe results in the error
> 
>     find-file-noselect: Wrong type argument: stringp, nil
> 
> whereas, if Step 2 is omitted, Forms Mode works correctly.

Thanks, I think I fixed this on the emacs-25 branch.