[patch]syndication_feeds's bug for TypeError

[junzhang.jn@…]

at feeds.py's line 35:

if callable(attr):
    try:
        return attr(obj)
    except TypeError:
        return attr()

this code will hide TypeError that zhe 'attr(obj)' function throws.
so , i use below code to fix the little bug.

if callable(attr):
    if hasattr( attr , 'func_code' ):
        argcount = attr.func_code.co_argcount
    else:
        argcount = attr.__call__.func_code.co_argcount
    if argcount == 2:
        # one is self
        return attr(obj)
    else:
        return attr()

[Adrian Holovaty]

(In [2341]) Fixed #1046 -- Made syndication feed framework not swallow TypeErrors in functions. Thanks, junzhang.jn