Contiki-NG: Fix coap_resolve_address_info

[kkrentz]

addr_ip was declared as a pointer, but sometimes not used in this manner.

[mrdeep1]

Thanks for this fix.

It would be great if coap_resolve_address_info() could also resolve DNS provided names, but I have no idea as to how to do that in Contiki-NG.

[kkrentz]

Contiki-NG provides the resolv module. However, it may return RESOLV_STATUS_RESOLVING and provide the result later. This makes it difficult to use it here. Another complication is that modules are not usually compiled and only added on demand.

[mrdeep1]

Thanks for the feedback re resolv. I'll ignore doing this for now.