[neovim] Fix Neovim plugin to use terminal instead of --height

Close #1066
Close #1068

plugin/fzf.vim

@@ -389,8 +389,10 @@ try
   let use_height = has_key(dict, 'down') && !has('gui_running') &&
         \ !(has('nvim') || s:is_win || has('win32unix') || s:present(dict, 'up', 'left', 'right', 'window')) &&
         \ executable('tput') && filereadable('/dev/tty')
-  let has_term = has('nvim-0.2.1') || has('nvim') && !s:is_win || has('terminal') && has('patch-8.0.995')
-  let use_term = has_term && (has('gui_running') || s:is_win || !use_height && s:present(dict, 'down', 'up', 'left', 'right', 'window'))
+  let has_vim8_term = has('terminal') && has('patch-8.0.995')
+  let has_nvim_term = has('nvim-0.2.1') || has('nvim') && !s:is_win
+  let use_term = has_nvim_term ||
+    \ has_vim8_term && (has('gui_running') || s:is_win || !use_height && s:present(dict, 'down', 'up', 'left', 'right', 'window'))
   let use_tmux = (!use_height && !use_term || prefer_tmux) && !has('win32unix') && s:tmux_enabled() && s:splittable(dict)
   if prefer_tmux && use_tmux
     let use_height = 0