Bind non-essential in pcomplete to prevent tramp error

[Michael Albinus]

Hi,

Jürgen Hötzel has reported an error in pcomplete, see
<https://github.com/company-mode/company-mode/pull/487#issuecomment-195926034>.
The following patch in the emacs-25 branch fixes this:

--8<---------------cut here---------------start------------->8---
*** 
/usr/local/src/emacs-25/lisp/pcomplete.el.~d457fd9dc782465e1547f74021390c9d5951d6af~
        2016-03-13 11:24:57.162148275 +0100
--- /usr/local/src/emacs-25/lisp/pcomplete.el   2016-03-13 11:12:53.540170107 
+0100
***************
*** 501,507 ****
      (setq pcomplete-current-completions nil
          pcomplete-last-completion-raw nil)
      (catch 'pcompleted
!       (let* ((pcomplete-stub)
             pcomplete-seen pcomplete-norm-func
             pcomplete-args pcomplete-last pcomplete-index
             (pcomplete-autolist pcomplete-autolist)
--- 501,508 ----
      (setq pcomplete-current-completions nil
          pcomplete-last-completion-raw nil)
      (catch 'pcompleted
!       (let* ((non-essential t)
!              pcomplete-stub
             pcomplete-seen pcomplete-norm-func
             pcomplete-args pcomplete-last pcomplete-index
             (pcomplete-autolist pcomplete-autolist)
--8<---------------cut here---------------end--------------->8---

Is it OK to install the patch in the emacs-25 branch?

Best regards, Michael.