Localvariable

this fix issue https://github.com/serge-sans-paille/pythran/issues/255
On Mon, Aug 18, 2014 at 11:41:33PM -0700, pbrunet wrote:
> In pythran/backend.py:
> >          self.declarations = list()
> >          self.definitions = list()
> >          self.break_handlers = list()
> >          self.result = None
> > +        self.ldecls = set()
> Hum, it shows that there are some "bad type" in the code. Looking at ldecls
> use, it is more often a set so I will change all these list to set.
great!