[Ag] Use absolute path when 'autochdir' is set

Close #55

autoload/fzf/vim.vim

@@ -381,7 +381,7 @@ endfunction
 " ------------------------------------------------------------------
 function! s:ag_to_qf(line)
   let parts = split(a:line, ':')
-  return {'filename': parts[0], 'lnum': parts[1], 'col': parts[2],
+  return {'filename': &acd ? fnamemodify(parts[0], ':p') : parts[0], 'lnum': parts[1], 'col': parts[2],
         \ 'text': join(parts[3:], ':')}
 endfunction