Remove unnecessary suppression of "unchecked"

Eclipse reports a warning that this suppression is not necessary.

This reverts commit 01675359e02d01b3f64eed0eb155a5a977f52ae7.

Change-Id: I54f4b30c68ddeba96a0dd2206d5e08cc881547f6
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/cache/ForwardingRemovalListener.java b/gerrit-server/src/main/java/com/google/gerrit/server/cache/ForwardingRemovalListener.java
index b99648b..c98ddf9 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/cache/ForwardingRemovalListener.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/cache/ForwardingRemovalListener.java
@@ -52,7 +52,6 @@
     }
   }
 
-  @SuppressWarnings("unchecked")
   public void onRemoval(RemovalNotification<K, V> notification) {
     for (CacheRemovalListener<K, V> l : listeners) {
       l.onRemoval(pluginName, cacheName, notification);