In magit-insert-section, do not presume that CMD is git

Removing the magit-git-standard-options from magit-insert-section
because:

- the only use of magit-insert-section is inside magit-git-section
  that already add the magit-git-standard-options, we do not need to add
  them twice
- as wrote, magit-insert-section could be used for calling any cmd,
  that may not understand the option in magit-git-standard-options.

magit.el

@@ -821,7 +821,7 @@ CMD is an external command that will be run with ARGS as arguments"
 		(insert (propertize buffer-title 'face 'magit-section-title)
 			"\n"))
 	    (setq body-beg (point))
-	    (apply 'process-file cmd nil t nil (append magit-git-standard-options args))
+	    (apply 'process-file cmd nil t nil args)
 	    (if (not (eq (char-before) ?\n))
 		(insert "\n"))
 	    (if washer