nvim: Update vim-plug

While at it, ignore old plug file artifact.

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>

.gitignore

@@ -1,3 +1,4 @@
 tmux/.tmux/resurrect
 nvim/.config/nvim/plugged
 nvim/.config/nvim/.netrwhist
+plug.vim.old

nvim/.local/share/nvim/site/autoload/plug.vim

@@ -1338,9 +1338,10 @@ function! s:bar()
 endfunction
 
 function! s:logpos(name)
-  for i in range(4, line('$'))
+  let max = line('$')
+  for i in range(4, max > 4 ? max : 4)
     if getline(i) =~# '^[-+x*] '.a:name.':'
-      for j in range(i + 1, line('$'))
+      for j in range(i + 1, max > 5 ? max : 5)
         if getline(j) !~ '^ '
           return [i, j - 1]
         endif