fixup!: Poll the filesystem for new events

Scheduled task is not cancelled during plugin removal
since the future used in start() and stop() are different.
Fix to use the same ScheduledFuture instance.

Change-Id: I332d3e5d5ccd2a157de3c67202f4207f2d38b993
diff --git a/src/main/java/com/googlesource/gerrit/plugins/events/fsstore/FsListener.java b/src/main/java/com/googlesource/gerrit/plugins/events/fsstore/FsListener.java
index 7ed0c1b..543b9d9 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/events/fsstore/FsListener.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/events/fsstore/FsListener.java
@@ -45,7 +45,7 @@
     @Override
     public void start() {
       if (pollingInterval > 0) {
-        ScheduledFuture<?> future =
+        future =
             queue
                 .getDefaultQueue()
                 .scheduleAtFixedRate(