Various mostly bonjour related fixes

[Mark Doliner]

On Tue, Nov 29, 2011 at 7:21 PM, Ethan Blanton <elb at pidgin.im> wrote:
> Mark Doliner spake unto us the following wisdom:
>> I guess I'd prefer if we didn't commit these to 2.x.y.  Supporting
>> ipv6 for bonjour doesn't seem critical to me.
>
> Please clarify what you mean by "these".

I guess I meant all of them.  And I don't have a strong opinion about
this.  I guess I'm mostly saying that _I_ wouldn't have committed them
to 2.x.y.  It's probably not worth reverting the changes from 2.x.y.
And I'm not going to stop anyone from committing the remaining patches
to 2.x.y.  But we should be EXTREMELY careful not to cause other bugs.