jed: loosen build-depend on libslang2-dev >= 2.0.7

[G. Milde]

Forwarded message from "G. Milde" <milde at users.sourceforge.net>
> On 17.05.07, Rafael Laboissiere wrote:
> > Package: jed
> > Version: 0.99.18+dfsg.1-3 
> 
> > * Jörg Sommer <joerg at alea.gnuu.de> [2007-05-16 11:42]:
> 
> > > why do you force a build against libslang2-dev 2.0.7? What's the problem
> > > with prior versions? I don't see, why we need this.
> 
> > I probably had a reason for that when I did the change in SVN revision 655
> > but I can not remember why.  I will revert this in the next release.
> 
> If I remember right, the problem is segfaults with earlier versions if files
> are preparsed (byte-compiled) that use the "string $varible"$ syntax.

I found it in http://www.ruptured-duck.com/jed-users/msg01916.html

  slang-2.0.6 had a bug in the handling of byte-compiled files
  containing strings with the "$" suffix, e.g.,
   
      file = "$HOME/foo.sl"$;
  
  This bug was corrected in 2.0.7.
  
This is a *grave* bug, so please set up the requirement again.

Günter