Remove comment related translators in export back-ends

* lisp/ox-ascii.el (ascii):
* lisp/ox-latex.el (latex):
* lisp/ox-man.el (man):
* lisp/ox-md.el (md):
* lisp/ox-org.el (org):
* lisp/ox-texinfo.el (texinfo):

* contrib/lisp/ox-groff.el (groff): Remove `comment' and
`comment-block' translators.

`comment' and `comment-block' translators are not needed since both
commented lines and comment blocks do not appear anymore in the parse
tree.  See 69dd4301ab7aeb581968f1c7e75167338d024c8f.

contrib/lisp/ox-groff.el

@@ -50,8 +50,6 @@
     (center-block . org-groff-center-block)
     (clock . org-groff-clock)
     (code . org-groff-code)
-    (comment . (lambda (&rest args) ""))
-    (comment-block . (lambda (&rest args) ""))
     (drawer . org-groff-drawer)
     (dynamic-block . org-groff-dynamic-block)
     (entity . org-groff-entity)

lisp/ox-ascii.el

@@ -49,8 +49,6 @@
     (center-block . org-ascii-center-block)
     (clock . org-ascii-clock)
     (code . org-ascii-code)
-    (comment . (lambda (&rest args) ""))
-    (comment-block . (lambda (&rest args) ""))
     (drawer . org-ascii-drawer)
     (dynamic-block . org-ascii-dynamic-block)
     (entity . org-ascii-entity)

lisp/ox-latex.el

@@ -43,8 +43,6 @@
     (center-block . org-latex-center-block)
     (clock . org-latex-clock)
     (code . org-latex-code)
-    (comment . (lambda (&rest args) ""))
-    (comment-block . (lambda (&rest args) ""))
     (drawer . org-latex-drawer)
     (dynamic-block . org-latex-dynamic-block)
     (entity . org-latex-entity)

lisp/ox-man.el

@@ -55,8 +55,6 @@
     (center-block . org-man-center-block)
     (clock . org-man-clock)
     (code . org-man-code)
-    (comment . (lambda (&rest args) ""))
-    (comment-block . (lambda (&rest args) ""))
     (drawer . org-man-drawer)
     (dynamic-block . org-man-dynamic-block)
     (entity . org-man-entity)

lisp/ox-md.el

@@ -1,6 +1,6 @@
 ;;; ox-md.el --- Markdown Back-End for Org Export Engine
 
-;; Copyright (C) 2012-2014 Free Software Foundation, Inc.
+;; Copyright (C) 2012-2015 Free Software Foundation, Inc.
 
 ;; Author: Nicolas Goaziou <n.goaziou@gmail.com>
 ;; Keywords: org, wp, markdown
@@ -68,8 +68,6 @@ This variable can be set to either `atx' or `setext'."
 		(org-open-file (org-md-export-to-markdown nil s v)))))))
   :translate-alist '((bold . org-md-bold)
 		     (code . org-md-verbatim)
-		     (comment . (lambda (&rest args) ""))
-		     (comment-block . (lambda (&rest args) ""))
 		     (example-block . org-md-example-block)
 		     (export-block . org-md-export-block)
 		     (fixed-width . org-md-example-block)

lisp/ox-org.el

@@ -57,8 +57,6 @@ setting of `org-html-htmlize-output-type' is 'css."
     (center-block . org-org-identity)
     (clock . org-org-identity)
     (code . org-org-identity)
-    (comment . (lambda (&rest args) ""))
-    (comment-block . (lambda (&rest args) ""))
     (diary-sexp . org-org-identity)
     (drawer . org-org-identity)
     (dynamic-block . org-org-identity)

lisp/ox-texinfo.el

@@ -39,8 +39,6 @@
     (center-block . org-texinfo-center-block)
     (clock . org-texinfo-clock)
     (code . org-texinfo-code)
-    (comment . (lambda (&rest args) ""))
-    (comment-block . (lambda (&rest args) ""))
     (drawer . org-texinfo-drawer)
     (dynamic-block . org-texinfo-dynamic-block)
     (entity . org-texinfo-entity)