configuration socket reconnects infinitely when using cached config

The connection to the REST configuration socket is infinitely retried when a cached configuration is used. This is because the refresh_config_cache function calls apply_vbucket_config; which changes the vbucket configuration and relocates the buffers, but does not tell the instance to stop trying to connect to the REST node.

The fix is to make it call the function which is called whenever a new configuration is received over the socket, and optionally close the socket and/or timers when the configuration is properly received.