Avoid presenting verbose command output as error

References https://github.com/tpope/vim-fugitive/issues/1643

autoload/fugitive.vim

@@ -1641,7 +1641,7 @@ function! s:ReplaceCmd(cmd) abort
   let temp = tempname()
   let [err, exec_error] = s:TempCmd(temp, a:cmd)
   if exec_error
-    call s:throw((len(err) ? err : filereadable(temp) ? join(readfile(temp), ' ') : 'unknown error running ' . a:cmd))
+    call s:throw((len(err) ? err : 'unknown error running ' . a:cmd))
   endif
   setlocal noswapfile
   silent exe 'lockmarks keepalt 0read ++edit' s:fnameescape(temp)