haddock fails to parse {- # ... #-} (note the space) pragma

**Original reporter**: _slyfox@<hidden>_

The problem was found on xmonad-0.9.2 haddock failure.

Minimal complete test looks as such:

``` haskell
$ haddock Fail.hs 

Fail.hs:1:3: parse error on input `#'
$ cat Fail.hs
{- # OPTIONS_GHC -fglasgow-exts    #-}

module Fail where
```

Reproducible with haddock-2.7.2 and 2.9.2.
