add Unplug

refer to junegunn/vim-plug#469 (comment)

.vimrc

@@ -108,6 +108,16 @@ if has("gui_running")
     set guicursor=n-v-c:ver5    " 设置光标为竖线
 endif
 
+"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
+" 卸载默认插件Unplug
+"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
+function! s:deregister(repo)
+  let repo = substitute(a:repo, '[\/]\+$', '', '')
+  let name = fnamemodify(repo, ':t:s?\.git$??')
+  call remove(g:plugs, name)
+endfunction
+command! -nargs=1 -bar Unplug call s:deregister(<args>)
+
 """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
 " 插件列表
 """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""