haskell-mode: fill-pagagraph breaks multi-line comments

[bremner]

Antti-Juhani Kaijanaho writes (http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=575081)

 {- lorem ipsum hgfh yjfgh yjthj ythygjty 6utyfg u6thtyj rhtyh rt46 hty y5rth trfdtrd htr trhr -}

gets rewritten by fill-paragraph (M-q) as

{- lorem ipsum hgfh yjfgh yjthj ythygjty 6utyfg u6thtyj rhtyh rt46 hty
{- y5rth trfdtrd htr trhr -}

This problem is still present for me in 2.8.0 with turn-on-haskell-indentation