wgengine: perform router reconfig for netlog-only changes (#6118)

If the network logging configruation changes (and nothing else)
we will tear down the network logger and start it back up.
However, doing so will lose the router configuration state.
Manually reconfigure it with the routing state.

Signed-off-by: Joe Tsai <joetsai@digital-static.net>

wgengine/userspace.go

@@ -956,6 +956,7 @@ func (e *userspaceEngine) Reconfig(cfg *wgcfg.Config, routerCfg *router.Config,
 		if err := e.networkLogger.Startup(cfg.NodeID, nid, tid, e.tundev, e.magicConn); err != nil {
 			e.logf("wgengine: Reconfig: error starting up network logger: %v", err)
 		}
+		e.networkLogger.ReconfigRoutes(routerCfg)
 	}
 
 	if routerChanged {