CHANGELOG-3.4: remove blank line

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>

CHANGELOG-3.4.md

@@ -177,7 +177,6 @@ See [security doc](https://github.com/coreos/etcd/blob/master/Documentation/op-g
   - e.g. `--logger=zap --log-outputs=a.log` will log server operations in [JSON-encoded format](https://godoc.org/go.uber.org/zap#NewProductionEncoderConfig) and writes logs to the specified file `a.log`.
   - e.g. `--logger=zap --log-outputs=a.log,b.log,c.log,stdout` [writes server logs to multiple files `a.log`, `b.log` and `c.log` at the same time](https://github.com/coreos/etcd/pull/9579) and outputs to `stdout`, in [JSON-encoded format](https://godoc.org/go.uber.org/zap#NewProductionEncoderConfig).
   - e.g. `--logger=zap --log-outputs=/dev/null` will discard all server logs.
-
 - Fix [`mvcc` "unsynced" watcher restore operation](https://github.com/coreos/etcd/pull/9281).
   - "unsynced" watcher is watcher that needs to be in sync with events that have happened.
   - That is, "unsynced" watcher is the slow watcher that was requested on old revision.