Fix for using Vundle in Windows setting g:bundle_dir to a network path

autoload/vundle/config.vim

@@ -198,6 +198,7 @@ func! s:rtp_add_a()
   let appends = join(paths, '/after,').'/after'
   exec 'set rtp^='.fnameescape(prepends)
   exec 'set rtp+='.fnameescape(appends)
+  let &rtp = substitute(&rtp, ',\\', ',\\\\', 'g')
 endf