conn_mgr now allows applications to request that ifaces be ignored.
This commit changes the echo_server sample to use this feature to
filter out the tunnel iface, instead of manually filtering events
generated by it.
This will allow the echo_server sample to remain compatible with
planned changes to conn_mgr, namely a switch from events being
fired for every individual iface that goes up or down, to only
being fired when connectivity is gained or completely lost.
Signed-off-by: Georges Oates_Larsen <georges.larsen@nordicsemi.no>
5350d417e9