elscreen require error

When I load elscreen with `(require 'elscreen)`.

But got this error:

```
Debugger entered--Lisp error: (wrong-type-argument consp nil)
  byte-code
  #<subr require>(elscreen nil t)
  ad-Advice-require(#<subr require> elscreen nil t)
  apply(ad-Advice-require #<subr require> (elscreen nil t))
  require(elscreen nil t)
  (not (require 'elscreen nil 't))
```
