make ipfamily configurable

[genofire]

acme on ipv6-only infrastructure is not possible ATM

---

workaround:
add:

            httpc:set_options([{ipfamily, inet6}]),

here:

p1_acme/src/p1_acme.erl

Lines 600 to 601 in 5ca4be1

	?DEBUG("HTTP request: ~p", [Request]),
	case httpc:request(Method, URL,

and recompile with erlc

[genofire]

And again i need to build this workaround ;(

[genofire]

And again - ejabberd expired certs ,(

[Neustradamus]

@prefiks: What do you think?