The previous patch removed module-gconf's dependency on the userdata
pointer of the free callback, and that was the only place where the
userdata pointer of pa_free2_cb_t was used, so now there's no need for
pa_free2_cb_t in pa_hashmap_free(). Using pa_free_cb_t instead allows
removing a significant amount of repetitive code.
The Apple TV for example uses a non-default port, but we previously ignored
this. We now correctly parse the server string but in so doing, we end up
parsing the address twice. As we need a pure IP/hostname of the device itself
to use in our requests, this is somewhat unavoidable.
Sadly there are still other problems with Apple TVs, but this is still
one step closer.
Fixes part of #950
