extraInitialRoutes() was meant to preserve only the fake IP route
(240.0.0.0/8) across TUN rebuilds, but it re-injected any initial
route missing from the current set. When the management server
advertised exit node routes (0.0.0.0/0) that were later filtered
by the route selector, extraInitialRoutes() re-added them, causing
the Android VPN to capture all traffic with no peer to handle it.
Store the fake IP route explicitly and append only that in notify(),
removing the overly broad initial route diffing.
