logtail: we missed a case for the backoff timer.

We want to run bo.Backoff() after every upload, regardless. If
upload==true but err!=nil, we weren't backing off, which caused some
very-high-throughput log upload retries in bad network conditions.

Updates #282.

Signed-off-by: Avery Pennarun <apenwarr@tailscale.com>

logtail/logtail.go

@@ -273,10 +273,10 @@ func (l *logger) uploading(ctx context.Context) {
 			if err != nil {
 				fmt.Fprintf(l.stderr, "logtail: upload: %v\n", err)
 			}
+			l.bo.BackOff(ctx, err)
 			if uploaded {
 				break
 			}
-			l.bo.BackOff(ctx, err)
 		}
 
 		select {