Fix bug when completing file names

* lisp/minibuffer.el (completion--nth-completion): Fix bug when
requote function is needed.
2 jobs for scratch/a-modest-completion-redesign-proposal in 43 minutes and 22 seconds (queued for 3 seconds)
latest
Status Job ID Name Coverage
  Test
failed #4184
test-all

00:43:00

failed #4185
test-filenotify-gio

00:43:21

 
Name Stage Failure
failed
test-filenotify-gio Test
Makefile:152: recipe for target 'cus-load.el' failed
make[2]: *** [cus-load.el] Error 255
make[2]: Leaving directory '/builds/emacs/emacs/lisp'
make[1]: *** [lisp] Error 2
Makefile:411: recipe for target 'lisp' failed
make[1]: Leaving directory '/builds/emacs/emacs'
Makefile:1117: recipe for target 'bootstrap' failed
make: *** [bootstrap] Error 2
ERROR: Job failed: exit code 1
failed
test-all Test
Makefile:152: recipe for target 'cus-load.el' failed
make[2]: *** [cus-load.el] Error 255
make[2]: Leaving directory '/builds/emacs/emacs/lisp'
Makefile:411: recipe for target 'lisp' failed
make[1]: *** [lisp] Error 2
make[1]: Leaving directory '/builds/emacs/emacs'
make: *** [bootstrap] Error 2
Makefile:1117: recipe for target 'bootstrap' failed
ERROR: Job failed: exit code 1