Fix regression in `get_listen_address`
This logic should check if;
- user did not explicitly specify any listening address
- and user did specify a listening interface
in that case; we need to get ip address from
If both address and interface is not specified, then the default should be
0.0.0.0 (all interfaces).
config.listen_address returns a value (default value) anyway,
that's why the try/catch block there won't work anymore.
It'd also be better if we have tests for this.