Support 7.4.52

Author: janlazo

plug.vim

@@ -1998,7 +1998,9 @@ endfunction
 
 function! plug#shellescape(arg, ...)
   let opts = get(a:000, 0, {})
-  let opts = type(opts) == s:TYPE.dict ? opts : {}
+  if type(opts) != s:TYPE.dict
+    let opts = {}
+  endif
   let shell = get(opts, 'shell', s:is_win ? 'cmd.exe' : 'sh')
   let script = get(opts, 'script', 1)
   if shell =~# 'cmd\.exe$'