Bug in Maxima interface wrt polylog

[rws]

sage: bool(x*polylog(x,x)==0)
...
/home/ralf/sage/local/lib/python2.7/site-packages/sage/symbolic/expression_conversions.pyc in composition(self, ex, operator)
    644         #FIXME: consider stripping pyobjects() in ops
    645         if hasattr(operator, self.name_init + "evaled_"):
--> 646             return getattr(operator, self.name_init + "evaled_")(*ops)
    647         else:
    648             ops = [self(_) for _ in ops]

/home/ralf/sage/local/lib/python2.7/site-packages/sage/functions/log.pyc in _maxima_init_evaled_(self, *args)
    451 
    452         n, x = args_maxima
--> 453         if int(n) in [1,2,3]:
    454             return 'li[%s](%s)'%(n, x)
    455         else:

ValueError: invalid literal for int() with base 10: '_SAGE_VAR_x'