CID 1472584: Error handling issues in check_descriptor_ipaddress_changed()

It looks like Coverity wants us to check the return value on relay_find_addr_to_publish.

 *** CID 1472584:  Error handling issues  (CHECKED_RETURN)
/src/feature/relay/router.c: 2700 in check_descriptor_ipaddress_changed()
2694           previous = &my_ri->ipv6_addr;
2695         }
2696     
2697         /* Attempt to discovery the publishable address for the family which will
2698          * actively attempt to discover the address if we are configured with a
2699          * port for the family. */
>>>     CID 1472584:  Error handling issues  (CHECKED_RETURN)
>>>     Calling "relay_find_addr_to_publish" without checking return value (as is done elsewhere 4 out of 5 times).
2700         relay_find_addr_to_publish(get_options(), family, RELAY_FIND_ADDR_NO_FLAG,
2701                                    &current);
2702     

Assigning to @dgoulet, but please let me know if you want me to do this.