ns_config_rep:init calls ns_config:reannounce, which can time out.

And since errors in init will bring down everything, this is bad.

Options:

1. Call it after init
2. Make it asynchronous
3. Wrap it in a try
4. Increase the timeout beyond the default 5s gen_server:call timeout

It's only called from ns_config_rep right now, so if we're not relying on the reannounce happening before other processes start, we can just make it asynchronous. 1 and 3 will potentially have the same problems if we're relying on the reannounce's actually completing before dependent processes start.