XDCR - topologySvc should use timer instead of ticker

Looking at logs from MB-48884 on the stuck node, I noticed a bunch of goroutines stuck at a select and not giving up as they should:

		timeout := time.NewTicker(1 * time.Second)

		if bw.source {

			select {   <--

			case chRaw.(chan service_def.SourceNotification) <- notification:

			// sent

			case <-timeout.C:

				// provide a bail out path

				notification.Recycle()

				continue

This should be using a timer instead of a ticker because it's only meant to trigger once.
According to golang, tickers can

The ticker will adjust the time interval or drop ticks to make up for slow receivers

It's very unlikely for the ticker to drop so many ticks but regardless this needs to be a Timer anyway.