[#492] node: Never go offline on application shutdown

Application can be shut down often, it is undesirable to send status changes
on a transaction every time. Control API should be used before shutdown for
this purpose.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

cmd/neofs-node/main.go

@@ -89,10 +89,6 @@ func shutdown(c *cfg) {
 		closer()
 	}
 
-	if c.cfgNetmap.goOfflineEnabled {
-		goOffline(c)
-	}
-
 	c.wg.Wait()
 }